---
_id: '11518'
abstract:
- lang: eng
text: "We present spectroscopic follow-up observations of CR7 with ALMA, targeted
at constraining the infrared (IR) continuum and [C II]158 mm line-emission at
high spatial resolution matched to the HST/WFC3 imaging. CR7 is a luminous Lyα
emitting galaxy at z = 6.6 that consists of three separated UV-continuum components.
Our observations reveal several well-separated components of [C II] emission.
The two most luminous components in [C II] coincide with the brightest UV components
(A and B), blueshifted by »150 km s−1 with respect to the\r\npeak of Lyα emission.
Other [C II] components are observed close to UV clumps B and C and are blueshifted
by »300 and ≈80 km s−1 with respect to the systemic redshift. We do not detect
FIR continuum emission due to dust with a 3σ limiting luminosity LIR T L d 35
K 3.1 10 = <´ 10 ( ) . This allows us to mitigate uncertainties in the dust-corrected
SFR and derive SFRs for the three UV clumps A, B, and C of 28, 5, and 7 M yr−1.
All clumps have [C II] luminosities consistent within the scatter observed in
the local relation between SFR and L[ ] C II , implying that strong Lyα emission
does not necessarily anti-correlate with [C II] luminosity. Combining\r\nour measurements
with the literature, we show that galaxies with blue UV slopes have weaker [C
II] emission at fixed SFR, potentially due to their lower metallicities and/or
higher photoionization. Comparison with hydrodynamical simulations suggests that
CR7ʼs clumps have metallicities of 0.1 Z Z 0.2 < < . The observed ISM structure
of CR7 indicates that we are likely witnessing the build up of a central galaxy
in the early universe through complex accretion of satellites."
acknowledgement: 'We thank the referee for their constructive comments, which have
helped improve the quality and clarity of this work. We thank Raffaella Schneider
for comments on an earlier version of this paper. We thank Leindert Boogaard, Steven
Bos, Rychard Bouwens, and Renske Smit for discussions. J.M. acknowledges the support
of a Huygens PhD fellowship from Leiden University. D.S. acknowledges financial
support from the Netherlands Organisation for Scientific research (NWO) through
a Veni fellowship and from Lancaster University through an Early Career Internal
Grant A100679. A.F. acknowledges support from the ERC Advanced Grant INTERSTELLAR
H2020/740120. B.D. acknowledges financial support from NASA through the Astrophysics
Data Analysis Program (ADAP), grant number NNX12AE20G. Based on observations made
with ESO Telescopes at the La Silla Paranal Observatory under programme ID 294.A-5018.
This paper makes use of the following ALMA data: ADS/JAO.ALMA#2015.1.00122.S. ALMA
is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan),
together with NRC (Canada) and NSC and ASIAA (Taiwan), and KASI (Republic of Korea),
in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated
by ESO, AUI/NRAO, and NAOJ.'
article_number: '145'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Jorryt J
full_name: Matthee, Jorryt J
id: 7439a258-f3c0-11ec-9501-9df22fe06720
last_name: Matthee
orcid: 0000-0003-2871-127X
- first_name: D.
full_name: Sobral, D.
last_name: Sobral
- first_name: F.
full_name: Boone, F.
last_name: Boone
- first_name: H.
full_name: Röttgering, H.
last_name: Röttgering
- first_name: D.
full_name: Schaerer, D.
last_name: Schaerer
- first_name: M.
full_name: Girard, M.
last_name: Girard
- first_name: A.
full_name: Pallottini, A.
last_name: Pallottini
- first_name: L.
full_name: Vallini, L.
last_name: Vallini
- first_name: A.
full_name: Ferrara, A.
last_name: Ferrara
- first_name: B.
full_name: Darvish, B.
last_name: Darvish
- first_name: B.
full_name: Mobasher, B.
last_name: Mobasher
citation:
ama: Matthee JJ, Sobral D, Boone F, et al. ALMA reveals metals yet no dust within
multiple components in CR7. The Astrophysical Journal. 2017;851(2). doi:10.3847/1538-4357/aa9931
apa: Matthee, J. J., Sobral, D., Boone, F., Röttgering, H., Schaerer, D., Girard,
M., … Mobasher, B. (2017). ALMA reveals metals yet no dust within multiple components
in CR7. The Astrophysical Journal. IOP Publishing. https://doi.org/10.3847/1538-4357/aa9931
chicago: Matthee, Jorryt J, D. Sobral, F. Boone, H. Röttgering, D. Schaerer, M.
Girard, A. Pallottini, et al. “ALMA Reveals Metals yet No Dust within Multiple
Components in CR7.” The Astrophysical Journal. IOP Publishing, 2017. https://doi.org/10.3847/1538-4357/aa9931.
ieee: J. J. Matthee et al., “ALMA reveals metals yet no dust within multiple
components in CR7,” The Astrophysical Journal, vol. 851, no. 2. IOP Publishing,
2017.
ista: Matthee JJ, Sobral D, Boone F, Röttgering H, Schaerer D, Girard M, Pallottini
A, Vallini L, Ferrara A, Darvish B, Mobasher B. 2017. ALMA reveals metals yet
no dust within multiple components in CR7. The Astrophysical Journal. 851(2),
145.
mla: Matthee, Jorryt J., et al. “ALMA Reveals Metals yet No Dust within Multiple
Components in CR7.” The Astrophysical Journal, vol. 851, no. 2, 145, IOP
Publishing, 2017, doi:10.3847/1538-4357/aa9931.
short: J.J. Matthee, D. Sobral, F. Boone, H. Röttgering, D. Schaerer, M. Girard,
A. Pallottini, L. Vallini, A. Ferrara, B. Darvish, B. Mobasher, The Astrophysical
Journal 851 (2017).
date_created: 2022-07-07T08:48:04Z
date_published: 2017-12-21T00:00:00Z
date_updated: 2022-08-18T10:23:35Z
day: '21'
doi: 10.3847/1538-4357/aa9931
extern: '1'
external_id:
arxiv:
- '1709.06569'
intvolume: ' 851'
issue: '2'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- dark ages
- reionization
- 'first stars – galaxies: formation – galaxies: high-redshift – galaxies: ISM – galaxies:
kinematics and dynamics'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1709.06569
month: '12'
oa: 1
oa_version: Preprint
publication: The Astrophysical Journal
publication_identifier:
eissn:
- 1538-4357
issn:
- 0004-637X
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: ALMA reveals metals yet no dust within multiple components in CR7
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 851
year: '2017'
...
---
_id: '11519'
abstract:
- lang: eng
text: 'Faint Lyα emitters become increasingly rarer toward the reionization epoch
(z ∼ 6–7). However, observations from a very large (∼5 deg2) Lyα narrow-band survey
at z = 6.6 show that this is not the case for the most luminous emitters, capable
of ionizing their own local bubbles. Here we present follow-up observations of
the two most luminous Lyα candidates in the COSMOS field: “MASOSA” and “CR7.”
We used X-SHOOTER, SINFONI, and FORS2 on the Very Large Telescope, and DEIMOS
on Keck, to confirm both candidates beyond any doubt. We find redshifts of z =
6.541 and z = 6.604 for “MASOSA” and “CR7,” respectively. MASOSA has a strong
detection in Lyα with a line width of 386 ± 30 km s−1 (FWHM) and with very high
EW0 (>200 Å), but undetected in the continuum, implying very low stellar mass
and a likely young, metal-poor stellar population. “CR7,” with an observed Lyα
luminosity of 1043.92±0.05 erg s−1 is the most luminous Lyα emitter ever found
at z > 6 and is spatially extended (∼16 kpc). “CR7” reveals a narrow Lyα line
with 266 ± 15 km s−1 FWHM, being detected in the near-infrared (NIR) (rest-frame
UV; β = −2.3 ± 0.1) and in IRAC/Spitzer. We detect a narrow He II 1640 Å emission
line (6σ, FWHM = 130 ± 30 km s−1 ) in CR7 which can explain the clear excess seen
in the J-band photometry (EW0 ∼ 80 Å). We find no other emission lines from the
UV to the NIR in our X-SHOOTER spectra (He II/O III] 1663 Å > 3 and He II/C III]
1908 Å > 2.5). We conclude that CR7 is best explained by a combination of a PopIII-like
population, which dominates the rest-frame UV and the nebular emission, and a
more normal stellar population, which presumably dominates the mass. Hubble Space
Telescope/WFC3 observations show that the light is indeed spatially separated
between a very blue component, coincident with Lyα and He II emission, and two
red components (∼5 kpc away), which dominate the mass. Our findings are consistent
with theoretical predictions of a PopIII wave, with PopIII star formation migrating
away from the original sites of star formation.'
acknowledgement: We thank the anonymous reviewer for useful and constructive comments
and suggestions which greatly improved the quality and clarity of our work. D.S.
acknowledges financial support from the Netherlands Organisation for Scientific
research (NWO) through a Veni fellowship, from FCT through a FCT Investigator Starting
Grant and Start-up Grant (IF/01154/2012/CP0189/CT0010), from FCT grant UID/FIS/04434/2013,
and from LSF and LKBF. J.M. acknowledges the award of a Huygens PhD fellowship.
H.R. acknowledges support from the ERC Advanced Investigator program NewClusters
321271. The authors thank Mark Dijkstra, Bhaskar Agarwal, Jarrett Johnson, Andrea
Ferrara, Jarle Brinchmann, Rebecca Bowler, George Becker, Emma Curtis-Lake, Milos
Milosavljevic, Raffaella Schneider, Paul Shapiro, and Erik Zackrisson for interesting,
stimulating and helpful discussions. The authors are extremely grateful to ESO for
the award of ESO DDT time (294.A-5018 and 294.A-5039) which allowed the spectroscopic
confirmation of both sources and the detailed investigation of their nature. Observations
are also based on data from W.M. Keck Observatory. The W.M. Keck Observatory is
operated as a scientific partnership of Caltech, the University of California and
the National Aeronautics and Space Administration. Based on observations obtained
with MegaPrime/Megacam, a joint project of CFHT and CEA/IRFU, at the Canada–France–Hawaii
Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada,
the Institut National des Science de lUnivers of the Centre National de la Recherche
Scientifique (CNRS) of France, and the University of Hawaii. This work is based
in part on data products produced at Terapix available at the Canadian Astronomy
Data Centre as part of the Canada–France–Hawaii Telescope Legacy Survey, a collaborative
project of NRC and CNRS. Based on data products from observations made with ESO
Telescopes at the La Silla Paranal Observatory under ESO programme IDs 294.A-5018,
294.A-5039, and 179.A-2005, and on data products produced by TERAPIX and the Cambridge
Astronomy Survey Unit on behalf of the UltraVISTA consortium. The authors acknowledge
the award of service time (SW2014b20) on the William Herschel Telescope (WHT). WHT
and its service programme are operated on the island of La Palma by the Isaac Newton
Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de
Astrofisica de Canarias.
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: David
full_name: Sobral, David
last_name: Sobral
- first_name: Jorryt J
full_name: Matthee, Jorryt J
id: 7439a258-f3c0-11ec-9501-9df22fe06720
last_name: Matthee
orcid: 0000-0003-2871-127X
- first_name: Behnam
full_name: Darvish, Behnam
last_name: Darvish
- first_name: Daniel
full_name: Schaerer, Daniel
last_name: Schaerer
- first_name: Bahram
full_name: Mobasher, Bahram
last_name: Mobasher
- first_name: Huub
full_name: Röttgering, Huub
last_name: Röttgering
- first_name: Sérgio
full_name: Santos, Sérgio
last_name: Santos
- first_name: Shoubaneh
full_name: Hemmati, Shoubaneh
last_name: Hemmati
citation:
ama: 'Sobral D, Matthee JJ, Darvish B, et al. Evidence for PopIII-like stellar populations
in the most luminous Lyα emitters at the epoch of reionisation: Spectroscopic
confirmation. The Astrophysical Journal. 2015;808(2):139. doi:10.1088/0004-637X/808/2/139'
apa: 'Sobral, D., Matthee, J. J., Darvish, B., Schaerer, D., Mobasher, B., Röttgering,
H., … Hemmati, S. (2015). Evidence for PopIII-like stellar populations in the
most luminous Lyα emitters at the epoch of reionisation: Spectroscopic confirmation.
The Astrophysical Journal. IOP Publishing. https://doi.org/10.1088/0004-637X/808/2/139'
chicago: 'Sobral, David, Jorryt J Matthee, Behnam Darvish, Daniel Schaerer, Bahram
Mobasher, Huub Röttgering, Sérgio Santos, and Shoubaneh Hemmati. “Evidence for
PopIII-like Stellar Populations in the Most Luminous Lyα Emitters at the Epoch
of Reionisation: Spectroscopic Confirmation.” The Astrophysical Journal.
IOP Publishing, 2015. https://doi.org/10.1088/0004-637X/808/2/139.'
ieee: 'D. Sobral et al., “Evidence for PopIII-like stellar populations in
the most luminous Lyα emitters at the epoch of reionisation: Spectroscopic confirmation,”
The Astrophysical Journal, vol. 808, no. 2. IOP Publishing, p. 139, 2015.'
ista: 'Sobral D, Matthee JJ, Darvish B, Schaerer D, Mobasher B, Röttgering H, Santos
S, Hemmati S. 2015. Evidence for PopIII-like stellar populations in the most luminous
Lyα emitters at the epoch of reionisation: Spectroscopic confirmation. The Astrophysical
Journal. 808(2), 139.'
mla: 'Sobral, David, et al. “Evidence for PopIII-like Stellar Populations in the
Most Luminous Lyα Emitters at the Epoch of Reionisation: Spectroscopic Confirmation.”
The Astrophysical Journal, vol. 808, no. 2, IOP Publishing, 2015, p. 139,
doi:10.1088/0004-637X/808/2/139.'
short: D. Sobral, J.J. Matthee, B. Darvish, D. Schaerer, B. Mobasher, H. Röttgering,
S. Santos, S. Hemmati, The Astrophysical Journal 808 (2015) 139.
date_created: 2022-07-07T09:00:58Z
date_published: 2015-07-28T00:00:00Z
date_updated: 2022-08-18T10:30:13Z
day: '28'
doi: 10.1088/0004-637X/808/2/139
extern: '1'
external_id:
arxiv:
- '1504.01734'
intvolume: ' 808'
issue: '2'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- dark ages
- reionization
- 'first stars – early universe – galaxies: evolution'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1504.01734
month: '07'
oa: 1
oa_version: Preprint
page: '139'
publication: The Astrophysical Journal
publication_identifier:
eissn:
- 1538-4357
issn:
- 0004-637X
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Evidence for PopIII-like stellar populations in the most luminous Lyα emitters
at the epoch of reionisation: Spectroscopic confirmation'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 808
year: '2015'
...
---
_id: '11520'
abstract:
- lang: eng
text: We present the spatially resolved Hα dynamics of 16 star-forming galaxies
at z ∼ 0.81 using the new KMOS multi-object integral field spectrograph on the
ESO Very Large Telescope. These galaxies, selected using 1.18 μm narrowband imaging
from the 10 deg2 CFHT-HiZELS survey of the SA 22 hr field, are found in a ∼4 Mpc
overdensity of Hα emitters and likely reside in a group/intermediate environment,
but not a cluster. We confirm and identify a rich group of star-forming galaxies
at z = 0.813 ± 0.003, with 13 galaxies within 1000 km s−1 of each other, and seven
within a diameter of 3 Mpc. All of our galaxies are “typical” star-forming galaxies
at their redshift, 0.8 ± 0.4 SFR$^*_{z = 0.8}$, spanning a range of specific star
formation rates (sSFRs) of 0.2–1.1 Gyr−1 and have a median metallicity very close
to solar of 12 + log(O/H) = 8.62 ± 0.06. We measure the spatially resolved Hα
dynamics of the galaxies in our sample and show that 13 out of 16 galaxies can
be described by rotating disks and use the data to derive inclination corrected
rotation speeds of 50–275 km s−1. The fraction of disks within our sample is 75%
± 8%, consistent with previous results based on Hubble Space Telescope morphologies
of Hα-selected galaxies at z ∼ 1 and confirming that disks dominate the SFR density
at z ∼ 1. Our Hα galaxies are well fitted by the z ∼ 1–2 Tully–Fisher (TF) relation,
confirming the evolution seen in the zero point. Apart from having, on average,
higher stellar masses and lower sSFRs, our group galaxies at z = 0.81 present
the same mass–metallicity and TF relation as z ∼ 1 field galaxies and are all
disk galaxies.
acknowledgement: 'We thank the referee for many helpful comments and suggestions which
greatly improved the clarity and quality of this work. D.S. acknowledges financial
support from the Netherlands Organisation for Scientific research (NWO) through
a Veni fellowship and also funding from the European Community Seventh Framework
Programme (FP7/2007-2013) under grant agreement number RG226604 (OPTICON) which
allowed access to CFHT time (proposals: 11BO29 & 12AO19). A.M.S. gratefully acknowledges
an STFC Advanced Fellowship through grant number ST/H005234/1. I.R.S., J.P.S., and
R.G.B. acknowledge support from the UK Science and Technology Facilities Council
(STFC) under ST/I001573/1. I.R.S. acknowledges STFC (ST/J001422/1), the ERC Advanced
Investigator program DUSTYGAL and a Royal Society/Wolfson Merit Award. P.N.B. acknowledges
support from STFC. R.M.S. acknowledges support from the grant ST/1001573/1. The
data presented here are based on observations with the KMOS spectrograph on the
ESO/VLT under program 60.A-9460 and can be accessed through the ESO data archive.
The authors also wish to acknowledge the help from Michael Hilker in preparing the
KMOS observations.'
article_number: '139'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: D.
full_name: Sobral, D.
last_name: Sobral
- first_name: A. M.
full_name: Swinbank, A. M.
last_name: Swinbank
- first_name: J. P.
full_name: Stott, J. P.
last_name: Stott
- first_name: Jorryt J
full_name: Matthee, Jorryt J
id: 7439a258-f3c0-11ec-9501-9df22fe06720
last_name: Matthee
orcid: 0000-0003-2871-127X
- first_name: R. G.
full_name: Bower, R. G.
last_name: Bower
- first_name: Ian
full_name: Smail, Ian
last_name: Smail
- first_name: P.
full_name: Best, P.
last_name: Best
- first_name: J. E.
full_name: Geach, J. E.
last_name: Geach
- first_name: R. M.
full_name: Sharples, R. M.
last_name: Sharples
citation:
ama: Sobral D, Swinbank AM, Stott JP, et al. The dynamics of z=0.8 H-alpha-selected
star-forming galaxies from KMOS/CF-HiZELS. The Astrophysical Journal. 2013;779(2).
doi:10.1088/0004-637x/779/2/139
apa: Sobral, D., Swinbank, A. M., Stott, J. P., Matthee, J. J., Bower, R. G., Smail,
I., … Sharples, R. M. (2013). The dynamics of z=0.8 H-alpha-selected star-forming
galaxies from KMOS/CF-HiZELS. The Astrophysical Journal. IOP Publishing.
https://doi.org/10.1088/0004-637x/779/2/139
chicago: Sobral, D., A. M. Swinbank, J. P. Stott, Jorryt J Matthee, R. G. Bower,
Ian Smail, P. Best, J. E. Geach, and R. M. Sharples. “The Dynamics of Z=0.8 H-Alpha-Selected
Star-Forming Galaxies from KMOS/CF-HiZELS.” The Astrophysical Journal.
IOP Publishing, 2013. https://doi.org/10.1088/0004-637x/779/2/139.
ieee: D. Sobral et al., “The dynamics of z=0.8 H-alpha-selected star-forming
galaxies from KMOS/CF-HiZELS,” The Astrophysical Journal, vol. 779, no.
2. IOP Publishing, 2013.
ista: Sobral D, Swinbank AM, Stott JP, Matthee JJ, Bower RG, Smail I, Best P, Geach
JE, Sharples RM. 2013. The dynamics of z=0.8 H-alpha-selected star-forming galaxies
from KMOS/CF-HiZELS. The Astrophysical Journal. 779(2), 139.
mla: Sobral, D., et al. “The Dynamics of Z=0.8 H-Alpha-Selected Star-Forming Galaxies
from KMOS/CF-HiZELS.” The Astrophysical Journal, vol. 779, no. 2, 139,
IOP Publishing, 2013, doi:10.1088/0004-637x/779/2/139.
short: D. Sobral, A.M. Swinbank, J.P. Stott, J.J. Matthee, R.G. Bower, I. Smail,
P. Best, J.E. Geach, R.M. Sharples, The Astrophysical Journal 779 (2013).
date_created: 2022-07-07T09:14:48Z
date_published: 2013-12-03T00:00:00Z
date_updated: 2022-08-18T10:43:07Z
day: '03'
doi: 10.1088/0004-637x/779/2/139
extern: '1'
external_id:
arxiv:
- '1310.3822'
intvolume: ' 779'
issue: '2'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- 'galaxies: evolution – galaxies'
- high-redshift – galaxies
- starburst
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1310.3822
month: '12'
oa: 1
oa_version: Preprint
publication: The Astrophysical Journal
publication_identifier:
eissn:
- 1538-4357
issn:
- 0004-637X
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: The dynamics of z=0.8 H-alpha-selected star-forming galaxies from KMOS/CF-HiZELS
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 779
year: '2013'
...