@inproceedings{10698, abstract = {This is the second of three talks describing the observation and characterization of a ferromagnetic moiré heterostructure based on twisted bilayer graphene aligned to hexagonal boron nitride. I will compare the qualitative and quantitative features of this observed quantum anomalous Hall state to traditional systems engineered from thin film (Bi,Sb)2Te3 topological insulators. In particular, we find that the measured electronic energy gap of ~30K is several times higher than the Curie temperature, consistent with a lack of disorder associated with magnetic dopants. In this system, the quantization arises from spontaneous ferromagnetic polarization into a single spin and valley moiré subband, which is topological despite the lack of spin orbit coupling. I will also discuss the observation of current induced switching, which allows the magnetic state of the heterostructure to be controllably reversed with currents as small as a few nanoamperes.}, author = {Serlin, Marec and Tschirhart, Charles and Polshyn, Hryhoriy and Zhang, Yuxuan and Zhu, Jiacheng and Huber, Martin E. and Balents, Leon and Watanabe, Kenji and Tanaguchi, Takashi and Young, Andrea}, booktitle = {APS March Meeting 2020}, location = {Denver, CO, United States}, number = {1}, publisher = {American Physical Society}, title = {{Intrinsic quantized anomalous Hall effect in a moiré heterostructure, part II: Temperature dependence and current switching}}, volume = {65}, year = {2020}, } @inproceedings{10699, abstract = {This is the third of three talks describing the observation and characterization of a ferromagnetic moiré heterostructure based on twisted bilayer graphene aligned to hexagonal boron nitride. In this segment I will present scanning probe magnetometry data acquired using a nanoSQUID-on-tip microscope, which provides ~150 nm spatial resolution and a field sensitivity of ~10 nT/rtHz. We study the distribution of magnetic domains within the device as a function of density, magnetic field training, and DC current. Our data allow us to constrain the magnitude of the orbital magnetic moment of the electrons in the QAH state. Comparison with simultaneously acquired transport data allows us to precisely correlate single domain dynamics with discrete jumps in the observed anomalous Hall signal.}, author = {Tschirhart, Charles and Serlin, Marec and Polshyn, Hryhoriy and Zhang, Yuxuan and Zhu, Jiacheng and Balents, Leon and Huber, Martin E. and Watanabe, Kenji and Tanaguchi, Takashi and Young, Andrea}, booktitle = {APS March Meeting 2020}, issn = {0003-0503}, location = {Denver, CO, United States}, number = {1}, publisher = {American Physical Society}, title = {{Intrinsic quantized anomalous Hall effect in a moiré heterostructure, part III: Scanning probe magnetometry}}, volume = {65}, year = {2020}, } @article{10701, abstract = {Partially filled Landau levels host competing electronic orders. For example, electron solids may prevail close to integer filling of the Landau levels before giving way to fractional quantum Hall liquids at higher carrier density1,2. Here, we report the observation of an electron solid with non-collinear spin texture in monolayer graphene, consistent with solidification of skyrmions3—topological spin textures characterized by quantized electrical charge4,5. We probe the spin texture of the solids using a modified Corbino geometry that allows ferromagnetic magnons to be launched and detected6,7. We find that magnon transport is highly efficient when one Landau level is filled (ν=1), consistent with quantum Hall ferromagnetic spin polarization. However, even minimal doping immediately quenches the magnon signal while leaving the vanishing low-temperature charge conductivity unchanged. Our results can be understood by the formation of a solid of charged skyrmions near ν=1, whose non-collinear spin texture leads to rapid magnon decay. Data near fractional fillings show evidence of several fractional skyrmion solids, suggesting that graphene hosts a highly tunable landscape of coupled spin and charge orders.}, author = {Zhou, Haoxin and Polshyn, Hryhoriy and Taniguchi, Takashi and Watanabe, Kenji and Young, Andrea F.}, issn = {1745-2481}, journal = {Nature Physics}, number = {2}, pages = {154--158}, publisher = {Springer Nature}, title = {{Skyrmion solids in monolayer graphene}}, doi = {10.1038/s41567-019-0729-8}, volume = {16}, year = {2020}, } @article{10862, abstract = {We consider the sum of two large Hermitian matrices A and B with a Haar unitary conjugation bringing them into a general relative position. We prove that the eigenvalue density on the scale slightly above the local eigenvalue spacing is asymptotically given by the free additive convolution of the laws of A and B as the dimension of the matrix increases. This implies optimal rigidity of the eigenvalues and optimal rate of convergence in Voiculescu's theorem. Our previous works [4], [5] established these results in the bulk spectrum, the current paper completely settles the problem at the spectral edges provided they have the typical square-root behavior. The key element of our proof is to compensate the deterioration of the stability of the subordination equations by sharp error estimates that properly account for the local density near the edge. Our results also hold if the Haar unitary matrix is replaced by the Haar orthogonal matrix.}, author = {Bao, Zhigang and Erdös, László and Schnelli, Kevin}, issn = {0022-1236}, journal = {Journal of Functional Analysis}, keywords = {Analysis}, number = {7}, publisher = {Elsevier}, title = {{Spectral rigidity for addition of random matrices at the regular edge}}, doi = {10.1016/j.jfa.2020.108639}, volume = {279}, year = {2020}, } @inbook{10865, abstract = {We introduce the notion of Witness Maps as a cryptographic notion of a proof system. A Unique Witness Map (UWM) deterministically maps all witnesses for an NP statement to a single representative witness, resulting in a computationally sound, deterministic-prover, non-interactive witness independent proof system. A relaxation of UWM, called Compact Witness Map (CWM), maps all the witnesses to a small number of witnesses, resulting in a “lossy” deterministic-prover, non-interactive proof-system. We also define a Dual Mode Witness Map (DMWM) which adds an “extractable” mode to a CWM. Our main construction is a DMWM for all NP relations, assuming sub-exponentially secure indistinguishability obfuscation ( iO ), along with standard cryptographic assumptions. The DMWM construction relies on a CWM and a new primitive called Cumulative All-Lossy-But-One Trapdoor Functions (C-ALBO-TDF), both of which are in turn instantiated based on iO and other primitives. Our instantiation of a CWM is in fact a UWM; in turn, we show that a UWM implies Witness Encryption. Along the way to constructing UWM and C-ALBO-TDF, we also construct, from standard assumptions, Puncturable Digital Signatures and a new primitive called Cumulative Lossy Trapdoor Functions (C-LTDF). The former improves up on a construction of Bellare et al. (Eurocrypt 2016), who relied on sub-exponentially secure iO and sub-exponentially secure OWF. As an application of our constructions, we show how to use a DMWM to construct the first leakage and tamper-resilient signatures with a deterministic signer, thereby solving a decade old open problem posed by Katz and Vaikunthanathan (Asiacrypt 2009), by Boyle, Segev and Wichs (Eurocrypt 2011), as well as by Faonio and Venturi (Asiacrypt 2016). Our construction achieves the optimal leakage rate of 1−o(1) .}, author = {Chakraborty, Suvradip and Prabhakaran, Manoj and Wichs, Daniel}, booktitle = {Public-Key Cryptography}, editor = {Kiayias, A}, isbn = {9783030453732}, issn = {1611-3349}, pages = {220--246}, publisher = {Springer Nature}, title = {{Witness maps and applications}}, doi = {10.1007/978-3-030-45374-9_8}, volume = {12110}, year = {2020}, } @article{10866, abstract = {Recent discoveries have shown that, when two layers of van der Waals (vdW) materials are superimposed with a relative twist angle between them, the electronic properties of the coupled system can be dramatically altered. Here, we demonstrate that a similar concept can be extended to the optics realm, particularly to propagating phonon polaritons–hybrid light-matter interactions. To do this, we fabricate stacks composed of two twisted slabs of a vdW crystal (α-MoO3) supporting anisotropic phonon polaritons (PhPs), and image the propagation of the latter when launched by localized sources. Our images reveal that, under a critical angle, the PhPs isofrequency curve undergoes a topological transition, in which the propagation of PhPs is strongly guided (canalization regime) along predetermined directions without geometric spreading. These results demonstrate a new degree of freedom (twist angle) for controlling the propagation of polaritons at the nanoscale with potential for nanoimaging, (bio)-sensing, or heat management.}, author = {Duan, Jiahua and Capote-Robayna, Nathaniel and Taboada-Gutiérrez, Javier and Álvarez-Pérez, Gonzalo and Prieto Gonzalez, Ivan and Martín-Sánchez, Javier and Nikitin, Alexey Y. and Alonso-González, Pablo}, issn = {1530-6992}, journal = {Nano Letters}, keywords = {Mechanical Engineering, Condensed Matter Physics, General Materials Science, General Chemistry, Bioengineering}, number = {7}, pages = {5323--5329}, publisher = {American Chemical Society}, title = {{Twisted nano-optics: Manipulating light at the nanoscale with twisted phonon polaritonic slabs}}, doi = {10.1021/acs.nanolett.0c01673}, volume = {20}, year = {2020}, } @article{10867, abstract = {In this paper we find a tight estimate for Gromov’s waist of the balls in spaces of constant curvature, deduce the estimates for the balls in Riemannian manifolds with upper bounds on the curvature (CAT(ϰ)-spaces), and establish similar result for normed spaces.}, author = {Akopyan, Arseniy and Karasev, Roman}, issn = {1687-0247}, journal = {International Mathematics Research Notices}, keywords = {General Mathematics}, number = {3}, pages = {669--697}, publisher = {Oxford University Press}, title = {{Waist of balls in hyperbolic and spherical spaces}}, doi = {10.1093/imrn/rny037}, volume = {2020}, year = {2020}, } @article{11054, abstract = {In recent years, the nuclear pore complex (NPC) has emerged as a key player in genome regulation and cellular homeostasis. New discoveries have revealed that the NPC has multiple cellular functions besides mediating the molecular exchange between the nucleus and the cytoplasm. In this review, we discuss non-transport aspects of the NPC focusing on the NPC-genome interaction, the extreme longevity of the NPC proteins, and NPC dysfunction in age-related diseases. The examples summarized herein demonstrate that the NPC, which first evolved to enable the biochemical communication between the nucleus and the cytoplasm, now doubles as the gatekeeper of cellular identity and aging.}, author = {Cho, Ukrae H. and HETZER, Martin W}, issn = {0896-6273}, journal = {Neuron}, keywords = {General Neuroscience}, number = {6}, pages = {899--911}, publisher = {Elsevier}, title = {{Nuclear periphery takes center stage: The role of nuclear pore complexes in cell identity and aging}}, doi = {10.1016/j.neuron.2020.05.031}, volume = {106}, year = {2020}, } @article{11055, abstract = {Vascular dysfunctions are a common feature of multiple age-related diseases. However, modeling healthy and pathological aging of the human vasculature represents an unresolved experimental challenge. Here, we generated induced vascular endothelial cells (iVECs) and smooth muscle cells (iSMCs) by direct reprogramming of healthy human fibroblasts from donors of different ages and Hutchinson-Gilford Progeria Syndrome (HGPS) patients. iVECs induced from old donors revealed upregulation of GSTM1 and PALD1, genes linked to oxidative stress, inflammation and endothelial junction stability, as vascular aging markers. A functional assay performed on PALD1 KD VECs demonstrated a recovery in vascular permeability. We found that iSMCs from HGPS donors overexpressed bone morphogenetic protein (BMP)−4, which plays a key role in both vascular calcification and endothelial barrier damage observed in HGPS. Strikingly, BMP4 concentrations are higher in serum from HGPS vs. age-matched mice. Furthermore, targeting BMP4 with blocking antibody recovered the functionality of the vascular barrier in vitro, hence representing a potential future therapeutic strategy to limit cardiovascular dysfunction in HGPS. These results show that iVECs and iSMCs retain disease-related signatures, allowing modeling of vascular aging and HGPS in vitro.}, author = {Bersini, Simone and Schulte, Roberta and Huang, Ling and Tsai, Hannah and HETZER, Martin W}, issn = {2050-084X}, journal = {eLife}, keywords = {General Immunology and Microbiology, General Biochemistry, Genetics and Molecular Biology, General Medicine, General Neuroscience}, publisher = {eLife Sciences Publications}, title = {{Direct reprogramming of human smooth muscle and vascular endothelial cells reveals defects associated with aging and Hutchinson-Gilford progeria syndrome}}, doi = {10.7554/elife.54383}, volume = {9}, year = {2020}, } @article{11056, abstract = {Aging of the circulatory system correlates with the pathogenesis of a large spectrum of diseases. However, it is largely unknown which factors drive the age-dependent or pathological decline of the vasculature and how vascular defects relate to tissue aging. The goal of the study is to design a multianalytical approach to identify how the cellular microenvironment (i.e., fibroblasts) and serum from healthy donors of different ages or Alzheimer disease (AD) patients can modulate the functionality of organ-specific vascular endothelial cells (VECs). Long-living human microvascular networks embedding VECs and fibroblasts from skin biopsies are generated. RNA-seq, secretome analyses, and microfluidic assays demonstrate that fibroblasts from young donors restore the functionality of aged endothelial cells, an effect also achieved by serum from young donors. New biomarkers of vascular aging are validated in human biopsies and it is shown that young serum induces angiopoietin-like-4, which can restore compromised vascular barriers. This strategy is then employed to characterize transcriptional/functional changes induced on the blood–brain barrier by AD serum, demonstrating the importance of PTP4A3 in the regulation of permeability. Features of vascular degeneration during aging and AD are recapitulated, and a tool to identify novel biomarkers that can be exploited to develop future therapeutics modulating vascular function is established.}, author = {Bersini, Simone and Arrojo e Drigo, Rafael and Huang, Ling and Shokhirev, Maxim N. and HETZER, Martin W}, issn = {2366-7478}, journal = {Advanced Biosystems}, keywords = {General Biochemistry, Genetics and Molecular Biology, Biomedical Engineering, Biomaterials}, number = {5}, publisher = {Wiley}, title = {{Transcriptional and functional changes of the human microvasculature during physiological aging and Alzheimer disease}}, doi = {10.1002/adbi.202000044}, volume = {4}, year = {2020}, } @article{11057, abstract = {During mitosis, transcription of genomic DNA is dramatically reduced, before it is reactivated during nuclear reformation in anaphase/telophase. Many aspects of the underlying principles that mediate transcriptional memory and reactivation in the daughter cells remain unclear. Here, we used ChIP-seq on synchronized cells at different stages after mitosis to generate genome-wide maps of histone modifications. Combined with EU-RNA-seq and Hi-C analyses, we found that during prometaphase, promoters, enhancers, and insulators retain H3K4me3 and H3K4me1, while losing H3K27ac. Enhancers globally retaining mitotic H3K4me1 or locally retaining mitotic H3K27ac are associated with cell type-specific genes and their transcription factors for rapid transcriptional activation. As cells exit mitosis, promoters regain H3K27ac, which correlates with transcriptional reactivation. Insulators also gain H3K27ac and CCCTC-binding factor (CTCF) in anaphase/telophase. This increase of H3K27ac in anaphase/telophase is required for posttranscriptional activation and may play a role in the establishment of topologically associating domains (TADs). Together, our results suggest that the genome is reorganized in a sequential order, in which histone methylations occur first in prometaphase, histone acetylation, and CTCF in anaphase/telophase, transcription in cytokinesis, and long-range chromatin interactions in early G1. We thus provide insights into the histone modification landscape that allows faithful reestablishment of the transcriptional program and TADs during cell division.}, author = {Kang, Hyeseon and Shokhirev, Maxim N. and Xu, Zhichao and Chandran, Sahaana and Dixon, Jesse R. and HETZER, Martin W}, issn = {0890-9369}, journal = {Genes & Development}, keywords = {Developmental Biology, Genetics}, number = {13-14}, pages = {913--930}, publisher = {Cold Spring Harbor Laboratory Press}, title = {{Dynamic regulation of histone modifications and long-range chromosomal interactions during postmitotic transcriptional reactivation}}, doi = {10.1101/gad.335794.119}, volume = {34}, year = {2020}, } @article{11058, abstract = {Nucleoporin 93 (Nup93) expression inversely correlates with the survival of triple-negative breast cancer patients. However, our knowledge of Nup93 function in breast cancer besides its role as structural component of the nuclear pore complex is not understood. Combination of functional assays and genetic analyses suggested that chromatin interaction of Nup93 partially modulates the expression of genes associated with actin cytoskeleton remodeling and epithelial to mesenchymal transition, resulting in impaired invasion of triple-negative, claudin-low breast cancer cells. Nup93 depletion induced stress fiber formation associated with reduced cell migration/proliferation and impaired expression of mesenchymal-like genes. Silencing LIMCH1, a gene responsible for actin cytoskeleton remodeling and up-regulated upon Nup93 depletion, partially restored the invasive phenotype of cancer cells. Loss of Nup93 led to significant defects in tumor establishment/propagation in vivo, whereas patient samples revealed that high Nup93 and low LIMCH1 expression correlate with late tumor stage. Our approach identified Nup93 as contributor of triple-negative, claudin-low breast cancer cell invasion and paves the way to study the role of nuclear envelope proteins during breast cancer tumorigenesis.}, author = {Bersini, Simone and Lytle, Nikki K and Schulte, Roberta and Huang, Ling and Wahl, Geoffrey M and HETZER, Martin W}, issn = {2575-1077}, journal = {Life Science Alliance}, keywords = {Health, Toxicology and Mutagenesis, Plant Science, Biochemistry, Genetics and Molecular Biology (miscellaneous), Ecology}, number = {1}, publisher = {Life Science Alliance}, title = {{Nup93 regulates breast tumor growth by modulating cell proliferation and actin cytoskeleton remodeling}}, doi = {10.26508/lsa.201900623}, volume = {3}, year = {2020}, } @article{11501, abstract = {We investigated the ultraviolet (UV) spectral properties of faint Lyman-α emitters (LAEs) in the redshift range 2.9 ≤ z ≤ 4.6, and we provide material to prepare future observations of the faint Universe. We used data from the MUSE Hubble Ultra Deep Survey to construct mean rest-frame spectra of continuum-faint (median MUV of −18 and down to MUV of −16), low stellar mass (median value of 108.4 M⊙ and down to 107 M⊙) LAEs at redshift z ≳ 3. We computed various averaged spectra of LAEs, subsampled on the basis of their observational (e.g., Lyα strength, UV magnitude and spectral slope) and physical (e.g., stellar mass and star-formation rate) properties. We searched for UV spectral features other than Lyα, such as higher ionization nebular emission lines and absorption features. We successfully observed the O III]λ1666 and [C III]λ1907+C III]λ1909 collisionally excited emission lines and the He IIλ1640 recombination feature, as well as the resonant C IVλλ1548,1551 doublet either in emission or P-Cygni. We compared the observed spectral properties of the different mean spectra and find the emission lines to vary with the observational and physical properties of the LAEs. In particular, the mean spectra of LAEs with larger Lyα equivalent widths, fainter UV magnitudes, bluer UV spectral slopes, and lower stellar masses show the strongest nebular emission. The line ratios of these lines are similar to those measured in the spectra of local metal-poor galaxies, while their equivalent widths are weaker compared to the handful of extreme values detected in individual spectra of z >  2 galaxies. This suggests that weak UV features are likely ubiquitous in high z, low-mass, and faint LAEs. We publicly released the stacked spectra, as they can serve as empirical templates for the design of future observations, such as those with the James Webb Space Telescope and the Extremely Large Telescope.}, author = {Feltre, Anna and Maseda, Michael V. and Bacon, Roland and Pradeep, Jayadev and Leclercq, Floriane and Kusakabe, Haruka and Wisotzki, Lutz and Hashimoto, Takuya and Schmidt, Kasper B. and Blaizot, Jeremy and Brinchmann, Jarle and Boogaard, Leindert and Cantalupo, Sebastiano and Carton, David and Inami, Hanae and Kollatschny, Wolfram and Marino, Raffaella A. and Matthee, Jorryt J and Nanayakkara, Themiya and Richard, Johan and Schaye, Joop and Tresse, Laurence and Urrutia, Tanya and Verhamme, Anne and Weilbacher, Peter M.}, issn = {1432-0746}, journal = {Astronomy & Astrophysics}, keywords = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: evolution / galaxies: high-redshift / ISM: lines and bands / ultraviolet: ISM / ultraviolet: galaxies}, publisher = {EDP Sciences}, title = {{The MUSE Hubble Ultra Deep Field Survey: XV. The mean rest-UV spectra of Lyα emitters at z > 3}}, doi = {10.1051/0004-6361/202038133}, volume = {641}, year = {2020}, } @article{11503, abstract = {Context. The Lyα emitter (LAE) fraction, XLAE, is a potentially powerful probe of the evolution of the intergalactic neutral hydrogen gas fraction. However, uncertainties in the measurement of XLAE are still under debate. Aims. Thanks to deep data obtained with the integral field spectrograph Multi Unit Spectroscopic Explorer (MUSE), we can measure the evolution of the LAE fraction homogeneously over a wide redshift range of z ≈ 3–6 for UV-faint galaxies (down to UV magnitudes of M1500 ≈ −17.75). This is a significantly fainter range than in former studies (M1500 ≤ −18.75) and it allows us to probe the bulk of the population of high-redshift star-forming galaxies. Methods. We constructed a UV-complete photometric-redshift sample following UV luminosity functions and measured the Lyα emission with MUSE using the latest (second) data release from the MUSE Hubble Ultra Deep Field Survey. Results. We derived the redshift evolution of XLAE for M1500 ∈ [ − 21.75; −17.75] for the first time with a equivalent width range EW(Lyα) ≥ 65 Å and found low values of XLAE ≲ 30% at z ≲ 6. The best-fit linear relation is XLAE = 0.07+0.06−0.03z − 0.22+0.12−0.24. For M1500 ∈ [ − 20.25; −18.75] and EW(Lyα) ≥ 25 Å, our XLAE values are consistent with those in the literature within 1σ at z ≲ 5, but our median values are systematically lower than reported values over the whole redshift range. In addition, we do not find a significant dependence of XLAE on M1500 for EW(Lyα) ≥ 50 Å at z ≈ 3–4, in contrast with previous work. The differences in XLAE mainly arise from selection biases for Lyman Break Galaxies (LBGs) in the literature: UV-faint LBGs are more easily selected if they have strong Lyα emission, hence XLAE is biased towards higher values when those samples are used. Conclusions. Our results suggest either a lower increase of XLAE towards z ≈ 6 than previously suggested, or even a turnover of XLAE at z ≈ 5.5, which may be the signature of a late or patchy reionization process. We compared our results with predictions from a cosmological galaxy evolution model. We find that a model with a bursty star formation (SF) can reproduce our observed LAE fractions much better than models where SF is a smooth function of time.}, author = {Kusakabe, Haruka and Blaizot, Jérémy and Garel, Thibault and Verhamme, Anne and Bacon, Roland and Richard, Johan and Hashimoto, Takuya and Inami, Hanae and Conseil, Simon and Guiderdoni, Bruno and Drake, Alyssa B. and Christian Herenz, Edmund and Schaye, Joop and Oesch, Pascal and Matthee, Jorryt J and Anna Marino, Raffaella and Borello Schmidt, Kasper and Pelló, Roser and Maseda, Michael and Leclercq, Floriane and Kerutt, Josephine and Mahler, Guillaume}, issn = {1432-0746}, journal = {Astronomy & Astrophysics}, keywords = {Space and Planetary Science, Astronomy and Astrophysics, dark ages / reionization / first stars / early Universe / cosmology: observations / galaxies: evolution / galaxies: high-redshift / intergalactic medium}, publisher = {EDP Sciences}, title = {{The MUSE Hubble Ultra Deep Field Survey: XIV. Evolution of the Lyα emitter fraction from z = 3 to z = 6}}, doi = {10.1051/0004-6361/201937340}, volume = {638}, year = {2020}, } @article{11504, abstract = {We present spatially resolved maps of six individually-detected Lyman α haloes (LAHs) as well as a first statistical analysis of the Lyman α (Lyα) spectral signature in the circum-galactic medium of high-redshift star-forming galaxies (−17.5 >  MUV >  −21.5) using the Multi-Unit Spectroscopic Explorer. Our resolved spectroscopic analysis of the LAHs reveals significant intrahalo variations of the Lyα line profile. Using a three-dimensional two-component model for the Lyα emission, we measured the full width at half maximum (FWHM), the peak velocity shift, and the asymmetry of the Lyα line in the core and in the halo of 19 galaxies. We find that the Lyα line shape is statistically different in the halo compared to the core (in terms of width, peak wavelength, and asymmetry) for ≈40% of our galaxies. Similarly to object-by-object based studies and a recent resolved study using lensing, we find a correlation between the peak velocity shift and the width of the Lyα line both at the interstellar and circum-galactic scales. This trend has been predicted by radiative transfer simulations of galactic winds as a result of resonant scattering in outflows. While there is a lack of correlation between the spectral properties and the spatial scale lengths of our LAHs, we find a correlation between the width of the line in the LAH and the halo flux fraction. Interestingly, UV bright galaxies (MUV <  −20) show broader, more redshifted, and less asymmetric Lyα lines in their haloes. The most significant correlation found is for the FWHM of the line and the UV continuum slope of the galaxy, suggesting that the redder galaxies have broader Lyα lines. The generally broad and red line shapes found in the halo component suggest that the Lyα haloes are powered either by scattering processes through an outflowing medium, fluorescent emission from outflowing cold clumps of gas, or a mix of both. Considering the large diversity of the Lyα line profiles observed in our sample and the lack of strong correlation, the interpretation of our results is still broadly open and underlines the need for realistic spatially resolved models of the LAHs.}, author = {Leclercq, Floriane and Bacon, Roland and Verhamme, Anne and Garel, Thibault and Blaizot, Jérémy and Brinchmann, Jarle and Cantalupo, Sebastiano and Claeyssens, Adélaïde and Conseil, Simon and Contini, Thierry and Hashimoto, Takuya and Herenz, Edmund Christian and Kusakabe, Haruka and Marino, Raffaella Anna and Maseda, Michael and Matthee, Jorryt J and Mitchell, Peter and Pezzulli, Gabriele and Richard, Johan and Schmidt, Kasper Borello and Wisotzki, Lutz}, issn = {1432-0746}, journal = {Astronomy & Astrophysics}, keywords = {Space and Planetary Science, Astronomy and Astrophysics galaxies: high-redshift / galaxies: formation / galaxies: evolution / cosmology: observations}, publisher = {EDP Sciences}, title = {{The MUSE Hubble Ultra Deep field survey: XIII. Spatially resolved spectral properties of Lyman α haloes around star-forming galaxies at z > 3}}, doi = {10.1051/0004-6361/201937339}, volume = {635}, year = {2020}, } @article{11513, abstract = {We report the spectroscopic confirmation of a new protocluster in the COSMOS field at z ∼ 2.2, COSMOS Cluster 2.2 (CC2.2), originally identified as an overdensity of narrowband selected Hα emitting candidates. With only two masks of Keck/MOSFIRE near-IR spectroscopy in both H (∼1.47–1.81 μm) and K (∼1.92–2.40 μm) bands (∼1.5 hr each), we confirm 35 unique protocluster members with at least two emission lines detected with S/N > 3. Combined with 12 extra members from the zCOSMOS-deep spectroscopic survey (47 in total), we estimate a mean redshift and a line-of-sight velocity dispersion of zmean = 2.23224 ± 0.00101 and σlos = 645 ± 69 km s−1 for this protocluster, respectively. Assuming virialization and spherical symmetry for the system, we estimate a total mass of Mvir ∼ (1–2) ×1014M⊙ for the structure. We evaluate a number density enhancement of δg ∼ 7 for this system and we argue that the structure is likely not fully virialized at z ∼ 2.2. However, in a spherical collapse model, δg is expected to grow to a linear matter enhancement of ∼1.9 by z = 0, exceeding the collapse threshold of 1.69, and leading to a fully collapsed and virialized Coma-type structure with a total mass of Mdyn(z = 0) ∼ 9.2 × 1014M⊙ by now. This observationally efficient confirmation suggests that large narrowband emission-line galaxy surveys, when combined with ancillary photometric data, can be used to effectively trace the large-scale structure and protoclusters at a time when they are mostly dominated by star-forming galaxies.}, author = {Darvish, Behnam and Scoville, Nick Z. and Martin, Christopher and Sobral, David and Mobasher, Bahram and Rettura, Alessandro and Matthee, Jorryt J and Capak, Peter and Chartab, Nima and Hemmati, Shoubaneh and Masters, Daniel and Nayyeri, Hooshang and O’Sullivan, Donal and Paulino-Afonso, Ana and Sattari, Zahra and Shahidi, Abtin and Salvato, Mara and Lemaux, Brian C. and Fèvre, Olivier Le and Cucciati, Olga}, issn = {1538-4357}, journal = {The Astrophysical Journal}, keywords = {Space and Planetary Science, Astronomy and Astrophysics}, number = {1}, publisher = {IOP Publishing}, title = {{Spectroscopic confirmation of a coma cluster progenitor at z ∼ 2.2}}, doi = {10.3847/1538-4357/ab75c3}, volume = {892}, year = {2020}, } @article{11528, abstract = {Ly α emission lines are typically found to be redshifted with respect to the systemic redshifts of galaxies, likely due to resonant scattering of Ly α photons. Here, we measure the average velocity offset for a sample of 96 z ≈ 3.3 Ly α emitters (LAEs) with a median Ly α flux (luminosity) of ≈10−17 erg cm−2 s−1 (⁠≈1042 erg s−1⁠) and a median star formation rate (SFR) of ≈1.3 M⊙ yr−1 (not corrected for possible dust extinction), detected by the Multi-Unit Spectroscopic Explorer as part of our MUSEQuBES circumgalactic medium (CGM) survey. By postulating that the stacked CGM absorption profiles of these LAEs, probed by eight background quasars, must be centred on the systemic redshift, we measure an average velocity offset, Voffset = 171\pm 8 km s−1, between the Ly α emission peak and the systemic redshift. The observed Voffset is lower by factors of ≈1.4 and ≈2.6 compared to the velocity offsets measured for narrow-band-selected LAEs and Lyman break galaxies, respectively, which probe galaxies with higher masses and SFRs. Consistent with earlier studies based on direct measurements for individual objects, we find that the Voffset is correlated with the full width at half-maximum of the red peak of the Ly α line, and anticorrelated with the rest-frame equivalent width. Moreover, we find that Voffset is correlated with SFR with a sub-linear scaling relation, Voffset∝SFR0.16±0.03⁠. Adopting the mass scaling for main-sequence galaxies, such a relation suggests that Voffset scales with the circular velocity of the dark matter haloes hosting the LAEs.}, author = {Muzahid, Sowgat and Schaye, Joop and Marino, Raffaella Anna and Cantalupo, Sebastiano and Brinchmann, Jarle and Contini, Thierry and Wendt, Martin and Wisotzki, Lutz and Zabl, Johannes and Bouché, Nicolas and Akhlaghi, Mohammad and Chen, Hsiao-Wen and Claeyssens, Adélaîde and Johnson, Sean and Leclercq, Floriane and Maseda, Michael and Matthee, Jorryt J and Richard, Johan and Urrutia, Tanya and Verhamme, Anne}, issn = {1365-2966}, journal = {Monthly Notices of the Royal Astronomical Society}, keywords = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: haloes, galaxies: high-redshift, quasars: absorption lines}, number = {2}, pages = {1013--1022}, publisher = {Oxford University Press}, title = {{MUSEQuBES: Calibrating the redshifts of Lyα emitters using stacked circumgalactic medium absorption profiles}}, doi = {10.1093/mnras/staa1347}, volume = {496}, year = {2020}, } @article{11529, abstract = {CR7 is among the most luminous Ly α emitters (LAEs) known at z = 6.6 and consists of at least three UV components that are surrounded by Ly α emission. Previous studies have suggested that it may host an extreme ionizing source. Here, we present deep integral field spectroscopy of CR7 with VLT/Multi Unit Spectroscopic Explorer (MUSE). We measure extended emission with a similar halo scale length as typical LAEs at z ≈ 5. CR7’s Ly α halo is clearly elongated along the direction connecting the multiple components, likely tracing the underlying gas distribution. The Ly α emission originates almost exclusively from the brightest UV component, but we also identify a faint kinematically distinct Ly α emitting region nearby a fainter component. Combined with new near-infrared data, the MUSE data show that the rest-frame Ly α equivalent width (EW) is ≈100 Å. This is a factor 4 higher than the EW measured in low-redshift analogues with carefully matched Ly α profiles (and thus arguably H I column density), but this EW can plausibly be explained by star formation. Alternative scenarios requiring active galactic nucleus (AGN) powering are also disfavoured by the narrower and steeper Ly α spectrum and much smaller IR to UV ratio compared to obscured AGN in other Ly α blobs. CR7’s Ly α emission, while extremely luminous, resembles the emission in more common LAEs at lower redshifts very well and is likely powered by a young metal-poor starburst.}, author = {Matthee, Jorryt J and Pezzulli, Gabriele and Mackenzie, Ruari and Cantalupo, Sebastiano and Kusakabe, Haruka and Leclercq, Floriane and Sobral, David and Richard, Johan and Wisotzki, Lutz and Lilly, Simon and Boogaard, Leindert and Marino, Raffaella and Maseda, Michael and Nanayakkara, Themiya}, issn = {1365-2966}, journal = {Monthly Notices of the Royal Astronomical Society}, keywords = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: evolution, galaxies: high-redshift, dark ages, reionization, first stars, cosmology: observations}, number = {2}, pages = {3043--3059}, publisher = {Oxford University Press}, title = {{The nature of CR7 revealed with MUSE: A young starburst powering extended Ly α emission at z = 6.6}}, doi = {10.1093/mnras/staa2550}, volume = {498}, year = {2020}, } @article{11530, abstract = {A prediction of the classic active galactic nucleus (AGN) unification model is the presence of ionization cones with different orientations depending on the AGN type. Confirmations of this model exist for present times, but it is less clear in the early Universe. Here, we use the morphology of giant Ly α nebulae around AGNs at redshift z ∼ 3 to probe AGN emission and therefore the validity of the AGN unification model at this redshift. We compare the spatial morphology of 19 nebulae previously found around type I AGNs with a new sample of four Ly α nebulae detected around type II AGNs. Using two independent techniques, we find that nebulae around type II AGNs are more asymmetric than around type I, at least at radial distances r > 30 physical kpc (pkpc) from the ionizing source. We conclude that the type I and type II AGNs in our sample show evidence of different surrounding ionizing geometries. This suggests that the classical AGN unification model is also valid for high-redshift sources. Finally, we discuss how the lack of asymmetry in the inner parts (r ≲ 30 pkpc) and the associated high values of the He II to Ly α ratios in these regions could indicate additional sources of (hard) ionizing radiation originating within or in proximity of the AGN host galaxies. This work demonstrates that the morphologies of giant Ly α nebulae can be used to understand and study the geometry of high-redshift AGNs on circumnuclear scales and it lays the foundation for future studies using much larger statistical samples.}, author = {den Brok, J S and Cantalupo, S and Mackenzie, R and Marino, R A and Pezzulli, G and Matthee, Jorryt J and Johnson, S D and Krumpe, M and Urrutia, T and Kollatschny, W}, issn = {1365-2966}, journal = {Monthly Notices of the Royal Astronomical Society}, keywords = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: active, galaxies: high-redshift, intergalactic medium, quasars: emission lines, quasars: general}, number = {2}, pages = {1874--1887}, publisher = {Oxford University Press}, title = {{Probing the AGN unification model at redshift z ∼ 3 with MUSE observations of giant Lyα nebulae}}, doi = {10.1093/mnras/staa1269}, volume = {495}, year = {2020}, } @article{11531, abstract = {While low-luminosity galaxies dominate number counts at all redshifts, their contribution to cosmic reionization is poorly understood due to a lack of knowledge of their physical properties. We isolate a sample of 35 z ≈ 4–5 continuum-faint Lyman-α emitters from deep VLT/MUSE spectroscopy and directly measure their H α emission using stacked Spitzer/IRAC Ch. 1 photometry. Based on Hubble Space Telescope imaging, we determine that the average UV continuum magnitude is fainter than −16 (≈ 0.01 L⋆), implying a median Lyman-α equivalent width of 259 Å. By combining the H α measurement with the UV magnitude, we determine the ionizing photon production efficiency, ξion, a first for such faint galaxies. The measurement of log10 (ξion [Hz erg−1]) = 26.28 (⁠+0.28−0.40⁠) is in excess of literature measurements of both continuum- and emission line-selected samples, implying a more efficient production of ionizing photons in these lower luminosity, Lyman-α-selected systems. We conclude that this elevated efficiency can be explained by stellar populations with metallicities between 4 × 10−4 and 0.008, with light-weighted ages less than 3 Myr.}, author = {Maseda, Michael V and Bacon, Roland and Lam, Daniel and Matthee, Jorryt J and Brinchmann, Jarle and Schaye, Joop and Labbe, Ivo and Schmidt, Kasper B and Boogaard, Leindert and Bouwens, Rychard and Cantalupo, Sebastiano and Franx, Marijn and Hashimoto, Takuya and Inami, Hanae and Kusakabe, Haruka and Mahler, Guillaume and Nanayakkara, Themiya and Richard, Johan and Wisotzki, Lutz}, issn = {1365-2966}, journal = {Monthly Notices of the Royal Astronomical Society}, keywords = {Space and Planetary Science, Astronomy and Astrophysics, Galaxies: evolution, Galaxies: high-redshift, Galaxies: ISM}, number = {4}, pages = {5120--5130}, publisher = {Oxford University Press}, title = {{Elevated ionizing photon production efficiency in faint high-equivalent-width Lyman-α emitters}}, doi = {10.1093/mnras/staa622}, volume = {493}, year = {2020}, }