[{"external_id":{"arxiv":["1802.06786"]},"year":"2021","keyword":["Astronomy and Astrophysics","galaxies","formation - galaxies","evolution - galaxies","star formation - galaxies","abundances"],"publication":"Nature Astronomy","status":"public","extern":"1","date_published":"2021-07-05T00:00:00Z","acknowledgement":"We thank the anonymous referee for their constructive comments. JM acknowledges the support of a Huygens PhD fellowship from Leiden University. We thank Jarle Brinchmann, Rob Crain and David Sobral for discussions. We acknowledge the use of the Topcat software (Taylor 2013) for assisting in rapid exploration of multi-dimensional datasets and the use of Python and its numpy, matplotlib and pandas packages.","publisher":"Springer Nature","article_processing_charge":"No","doi":"10.1038/s41550-021-01415-y","type":"journal_article","_id":"11585","date_updated":"2022-08-19T08:37:58Z","page":"984-985","quality_controlled":"1","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1802.06786"}],"arxiv":1,"month":"07","language":[{"iso":"eng"}],"oa":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ista":"Matthee JJ. 2021. Differences in galaxy colours are not just about the mass. Nature Astronomy. 5, 984–985.","chicago":"Matthee, Jorryt J. “Differences in Galaxy Colours Are Not Just about the Mass.” <i>Nature Astronomy</i>. Springer Nature, 2021. <a href=\"https://doi.org/10.1038/s41550-021-01415-y\">https://doi.org/10.1038/s41550-021-01415-y</a>.","mla":"Matthee, Jorryt J. “Differences in Galaxy Colours Are Not Just about the Mass.” <i>Nature Astronomy</i>, vol. 5, Springer Nature, 2021, pp. 984–85, doi:<a href=\"https://doi.org/10.1038/s41550-021-01415-y\">10.1038/s41550-021-01415-y</a>.","apa":"Matthee, J. J. (2021). Differences in galaxy colours are not just about the mass. <i>Nature Astronomy</i>. Springer Nature. <a href=\"https://doi.org/10.1038/s41550-021-01415-y\">https://doi.org/10.1038/s41550-021-01415-y</a>","ama":"Matthee JJ. Differences in galaxy colours are not just about the mass. <i>Nature Astronomy</i>. 2021;5:984-985. doi:<a href=\"https://doi.org/10.1038/s41550-021-01415-y\">10.1038/s41550-021-01415-y</a>","short":"J.J. Matthee, Nature Astronomy 5 (2021) 984–985.","ieee":"J. J. Matthee, “Differences in galaxy colours are not just about the mass,” <i>Nature Astronomy</i>, vol. 5. Springer Nature, pp. 984–985, 2021."},"oa_version":"Preprint","title":"Differences in galaxy colours are not just about the mass","day":"05","scopus_import":"1","author":[{"first_name":"Jorryt J","orcid":"0000-0003-2871-127X","last_name":"Matthee","full_name":"Matthee, Jorryt J","id":"7439a258-f3c0-11ec-9501-9df22fe06720"}],"date_created":"2022-07-14T13:13:39Z","article_type":"original","volume":5,"abstract":[{"text":"Observations show that star-forming galaxies reside on a tight three-dimensional plane between mass, gas-phase metallicity and star formation rate (SFR), which can be explained by the interplay between metal-poor gas inflows, SFR and outflows. However, different metals are released on different time-scales, which may affect the slope of this relation. Here, we use central, star-forming galaxies with Mstar = 109.0−10.5 M\f from the EAGLE hydrodynamical simulation to examine three-dimensional relations between mass, SFR and chemical enrichment using absolute and relative C, N, O and Fe abundances. We show that the scatter is smaller when gas-phase α-enhancement is used rather than metallicity. A similar plane also exists for stellar α-enhancement, implying that present-day specific SFRs are correlated with long time-scale star formation histories. Between z = 0 and 1, the α-enhancement plane is even more insensitive to redshift than the plane using metallicity. However, it evolves at z > 1 due to lagging iron yields. At fixed mass, galaxies with higher SFRs have star formation histories shifted toward late times, are more α-enhanced and this α-enhancement increases with redshift as observed. These findings suggest that relations between physical properties inferred from observations may be affected by systematic variations in α-enhancements.","lang":"eng"}],"intvolume":"         5","publication_status":"published","publication_identifier":{"eissn":["2397-3366"]}},{"volume":648,"date_created":"2022-07-06T09:07:06Z","article_type":"original","day":"16","scopus_import":"1","author":[{"first_name":"Themiya","full_name":"Nanayakkara, Themiya","last_name":"Nanayakkara"},{"first_name":"Jarle","full_name":"Brinchmann, Jarle","last_name":"Brinchmann"},{"last_name":"Boogaard","full_name":"Boogaard, Leindert","first_name":"Leindert"},{"first_name":"Rychard","full_name":"Bouwens, Rychard","last_name":"Bouwens"},{"first_name":"Sebastiano","last_name":"Cantalupo","full_name":"Cantalupo, Sebastiano"},{"full_name":"Feltre, Anna","last_name":"Feltre","first_name":"Anna"},{"first_name":"Wolfram","full_name":"Kollatschny, Wolfram","last_name":"Kollatschny"},{"full_name":"Marino, Raffaella Anna","last_name":"Marino","first_name":"Raffaella Anna"},{"first_name":"Michael","full_name":"Maseda, Michael","last_name":"Maseda"},{"last_name":"Matthee","full_name":"Matthee, Jorryt J","id":"7439a258-f3c0-11ec-9501-9df22fe06720","orcid":"0000-0003-2871-127X","first_name":"Jorryt J"},{"last_name":"Paalvast","full_name":"Paalvast, Mieke","first_name":"Mieke"},{"last_name":"Richard","full_name":"Richard, Johan","first_name":"Johan"},{"full_name":"Verhamme, Anne","last_name":"Verhamme","first_name":"Anne"}],"oa_version":"Published Version","title":"Exploring He II λ1640 emission line properties at z ∼2−4","publication_identifier":{"eissn":["1432-0746"],"issn":["0004-6361"]},"publication_status":"published","intvolume":"       648","abstract":[{"lang":"eng","text":"Deep optical spectroscopic surveys of galaxies provide a unique opportunity to investigate rest-frame ultra-violet (UV) emission line properties of galaxies at z ∼ 2 − 4.5. Here we combine VLT/MUSE Guaranteed Time Observations of the Hubble Deep Field South, Ultra Deep Field, COSMOS, and several quasar fields with other publicly available data from VLT/VIMOS and VLT/FORS2 to construct a catalogue of He II λ1640 emitters at z ≳ 2. The deepest areas of our MUSE pointings reach a 3σ line flux limit of 3.1 × 10−19 erg s−1 cm−2. After discarding broad-line active galactic nuclei, we find 13 He II λ1640 detections from MUSE with a median MUV = −20.1 and 21 tentative He II λ1640 detections from other public surveys. Excluding Lyα, all except two galaxies in our sample show at least one other rest-UV emission line, with C III] λ1907, λ1909 being the most prominent. We use multi-wavelength data available in the Hubble legacy fields to derive basic galaxy properties of our sample through spectral energy distribution fitting techniques. Taking advantage of the high-quality spectra obtained by MUSE (∼10 − 30 h of exposure time per pointing), we use photo-ionisation models to study the rest-UV emission line diagnostics of the He II λ1640 emitters. Line ratios of our sample can be reproduced by moderately sub-solar photo-ionisation models, however, we find that including effects of binary stars lead to degeneracies in most free parameters. Even after considering extra ionising photons produced by extreme sub-solar metallicity binary stellar models, photo-ionisation models are unable to reproduce rest-frame He II λ1640 equivalent widths (∼0.2 − 10 Å), thus additional mechanisms are necessary in models to match the observed He II λ1640 properties."}],"article_number":"A89","month":"04","arxiv":1,"citation":{"chicago":"Nanayakkara, Themiya, Jarle Brinchmann, Leindert Boogaard, Rychard Bouwens, Sebastiano Cantalupo, Anna Feltre, Wolfram Kollatschny, et al. “Exploring He II Λ1640 Emission Line Properties at z ∼2−4.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2019. <a href=\"https://doi.org/10.1051/0004-6361/201834565\">https://doi.org/10.1051/0004-6361/201834565</a>.","ista":"Nanayakkara T, Brinchmann J, Boogaard L, Bouwens R, Cantalupo S, Feltre A, Kollatschny W, Marino RA, Maseda M, Matthee JJ, Paalvast M, Richard J, Verhamme A. 2019. Exploring He II λ1640 emission line properties at z ∼2−4. Astronomy &#38; Astrophysics. 648, A89.","mla":"Nanayakkara, Themiya, et al. “Exploring He II Λ1640 Emission Line Properties at z ∼2−4.” <i>Astronomy &#38; Astrophysics</i>, vol. 648, A89, EDP Sciences, 2019, doi:<a href=\"https://doi.org/10.1051/0004-6361/201834565\">10.1051/0004-6361/201834565</a>.","apa":"Nanayakkara, T., Brinchmann, J., Boogaard, L., Bouwens, R., Cantalupo, S., Feltre, A., … Verhamme, A. (2019). Exploring He II λ1640 emission line properties at z ∼2−4. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href=\"https://doi.org/10.1051/0004-6361/201834565\">https://doi.org/10.1051/0004-6361/201834565</a>","ama":"Nanayakkara T, Brinchmann J, Boogaard L, et al. Exploring He II λ1640 emission line properties at z ∼2−4. <i>Astronomy &#38; Astrophysics</i>. 2019;648. doi:<a href=\"https://doi.org/10.1051/0004-6361/201834565\">10.1051/0004-6361/201834565</a>","short":"T. Nanayakkara, J. Brinchmann, L. Boogaard, R. Bouwens, S. Cantalupo, A. Feltre, W. Kollatschny, R.A. Marino, M. Maseda, J.J. Matthee, M. Paalvast, J. Richard, A. Verhamme, Astronomy &#38; Astrophysics 648 (2019).","ieee":"T. Nanayakkara <i>et al.</i>, “Exploring He II λ1640 emission line properties at z ∼2−4,” <i>Astronomy &#38; Astrophysics</i>, vol. 648. EDP Sciences, 2019."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","oa":1,"language":[{"iso":"eng"}],"_id":"11499","date_updated":"2022-07-19T09:36:08Z","type":"journal_article","article_processing_charge":"No","doi":"10.1051/0004-6361/201834565","publisher":"EDP Sciences","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1902.05960"}],"quality_controlled":"1","keyword":["Space and Planetary Science","Astronomy and Astrophysics","galaxies: ISM / galaxies: star formation / galaxies: evolution / galaxies: high-redshift"],"year":"2019","related_material":{"link":[{"url":"https://doi.org/10.1051/0004-6361/201834565e","relation":"erratum"}]},"external_id":{"arxiv":["1902.05960"]},"date_published":"2019-04-16T00:00:00Z","acknowledgement":"The authors wish to thank the referee for constructive comments that improved the paper substantially. We thank the BPASS team for making the stellar population models available. We thank Elizabeth Stanway, Claus Leitherer, Daniel Schaerer, Jorick Vink, and Nell Byler for insightful discussions. We thank the Lorentz Centre and the scientific organizers of the Characterizing galaxies with spectroscopy with a view for JWST workshop held at the Lorentz Centre in 2017 October, which promoted useful discussions in the wider community. TN, JB, and RB acknowledges the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) top grant TOP1.16.057. AF acknowledges support from the ERC via an Advanced Grant under grant agreement no. 339659-MUSICOS. JB acknowledges support by Fundação para a Ciência e a Tecnologia (FCT) through national funds (UID/FIS/04434/2013) and Investigador FCT contract IF/01654/2014/CP1215/CT0003, and by FEDER through COMPETE2020 (POCI-01-0145-FEDER-007672). JR acknowledges support from the ERC Starting grant 336736 (CALENDS). This research made use of astropy (http://www.astropy.org) a community-developed core Python package for Astronomy (Astropy Collaboration 2013, 2018) and pandas (McKinney 2010). Figures were generated using matplotlib (Hunter 2007) and seaborn (https://seaborn.pydata.org). Facilities: VLT (MUSE).","publication":"Astronomy & Astrophysics","status":"public","extern":"1"},{"scopus_import":"1","day":"26","author":[{"last_name":"Sobral","full_name":"Sobral, David","first_name":"David"},{"full_name":"Matthee, Jorryt J","id":"7439a258-f3c0-11ec-9501-9df22fe06720","last_name":"Matthee","orcid":"0000-0003-2871-127X","first_name":"Jorryt J"}],"title":"Predicting Lyα escape fractions with a simple observable: Lyα in emission as an empirically calibrated star formation rate indicator","oa_version":"Published Version","volume":623,"date_created":"2022-07-06T11:08:16Z","article_type":"original","intvolume":"       623","abstract":[{"text":"Lyman-α (Lyα) is intrinsically the brightest line emitted from active galaxies. While it originates from many physical processes, for star-forming galaxies the intrinsic Lyα luminosity is a direct tracer of the Lyman-continuum (LyC) radiation produced by the most massive O- and early-type B-stars (M⋆ ≳ 10 M⊙) with lifetimes of a few Myrs. As such, Lyα luminosity should be an excellent instantaneous star formation rate (SFR) indicator. However, its resonant nature and susceptibility to dust as a rest-frame UV photon makes Lyα very hard to interpret due to the uncertain Lyα escape fraction, fesc, Lyα. Here we explore results from the CAlibrating LYMan-α with Hα (CALYMHA) survey at z = 2.2, follow-up of Lyα emitters (LAEs) at z = 2.2 − 2.6 and a z ∼ 0−0.3 compilation of LAEs to directly measure fesc, Lyα with Hα. We derive a simple empirical relation that robustly retrieves fesc, Lyα as a function of Lyα rest-frame EW (EW0): fesc,Lyα = 0.0048 EW0[Å] ± 0.05 and we show that it constrains a well-defined anti-correlation between ionisation efficiency (ξion) and dust extinction in LAEs. Observed Lyα luminosities and EW0 are easy measurable quantities at high redshift, thus making our relation a practical tool to estimate intrinsic Lyα and LyC luminosities under well controlled and simple assumptions. Our results allow observed Lyα luminosities to be used to compute SFRs for LAEs at z ∼ 0−2.6 within ±0.2 dex of the Hα dust corrected SFRs. We apply our empirical SFR(Lyα,EW0) calibration to several sources at z ≥ 2.6 to find that star-forming LAEs have SFRs typically ranging from 0.1 to 20 M⊙ yr−1 and that our calibration might be even applicable for the most luminous LAEs within the epoch of re-ionisation. Our results imply high ionisation efficiencies (log10[ξion/Hz erg−1] = 25.4−25.6) and low dust content in LAEs across cosmic time, and will be easily tested with future observations with JWST which can obtain Hα and Hβ measurements for high-redshift LAEs.","lang":"eng"}],"publication_status":"published","publication_identifier":{"issn":["0004-6361"],"eissn":["1432-0746"]},"month":"03","arxiv":1,"article_number":"A157","oa":1,"language":[{"iso":"eng"}],"citation":{"ieee":"D. Sobral and J. J. Matthee, “Predicting Lyα escape fractions with a simple observable: Lyα in emission as an empirically calibrated star formation rate indicator,” <i>Astronomy &#38; Astrophysics</i>, vol. 623. EDP Sciences, 2019.","short":"D. Sobral, J.J. Matthee, Astronomy &#38; Astrophysics 623 (2019).","ama":"Sobral D, Matthee JJ. Predicting Lyα escape fractions with a simple observable: Lyα in emission as an empirically calibrated star formation rate indicator. <i>Astronomy &#38; Astrophysics</i>. 2019;623. doi:<a href=\"https://doi.org/10.1051/0004-6361/201833075\">10.1051/0004-6361/201833075</a>","apa":"Sobral, D., &#38; Matthee, J. J. (2019). Predicting Lyα escape fractions with a simple observable: Lyα in emission as an empirically calibrated star formation rate indicator. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href=\"https://doi.org/10.1051/0004-6361/201833075\">https://doi.org/10.1051/0004-6361/201833075</a>","mla":"Sobral, David, and Jorryt J. Matthee. “Predicting Lyα Escape Fractions with a Simple Observable: Lyα in Emission as an Empirically Calibrated Star Formation Rate Indicator.” <i>Astronomy &#38; Astrophysics</i>, vol. 623, A157, EDP Sciences, 2019, doi:<a href=\"https://doi.org/10.1051/0004-6361/201833075\">10.1051/0004-6361/201833075</a>.","ista":"Sobral D, Matthee JJ. 2019. Predicting Lyα escape fractions with a simple observable: Lyα in emission as an empirically calibrated star formation rate indicator. Astronomy &#38; Astrophysics. 623, A157.","chicago":"Sobral, David, and Jorryt J Matthee. “Predicting Lyα Escape Fractions with a Simple Observable: Lyα in Emission as an Empirically Calibrated Star Formation Rate Indicator.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2019. <a href=\"https://doi.org/10.1051/0004-6361/201833075\">https://doi.org/10.1051/0004-6361/201833075</a>."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","article_processing_charge":"No","doi":"10.1051/0004-6361/201833075","publisher":"EDP Sciences","_id":"11507","date_updated":"2022-07-19T09:37:20Z","type":"journal_article","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1803.08923"}],"quality_controlled":"1","year":"2019","external_id":{"arxiv":["1803.08923"]},"keyword":["Space and Planetary Science","Astronomy and Astrophysics","galaxies: high-redshift / galaxies: star formation / galaxies: statistics / galaxies: evolution / galaxies: formation / galaxies: ISM"],"publication":"Astronomy & Astrophysics","status":"public","extern":"1","acknowledgement":"We thank the anonymous referees for multiple comments and suggestions which have improved the manuscript. JM acknowledges the support of a Huygens PhD fellowship from Leiden University. We have benefited greatly from the publicly available programming language PYTHON, including the NUMPY & SCIPY (Van Der Walt et al. 2011; Jones et al. 2001), MATPLOTLIB (Hunter 2007) and ASTROPY (Astropy Collaboration 2013) packages, and the TOPCAT analysis program (Taylor 2013). The results and samples of LAEs used for this paper are publicly available (see e.g. Sobral et al. 2017, 2018a) and we also provide the toy model used as a PYTHON script.","date_published":"2019-03-26T00:00:00Z"}]