J/A+A/678/A26 z-GAL.I. Overview (Cox+, 2023)
z-GAL: A NOEMA spectroscopic redshift survey of bright Herschel galaxies.
I. Overview.
Cox P., Neri R., Berta S., Ismail D., Stanley F., Young A., Jin S.,
Bakx T., Beelen A., Dannerbauer H., Krips M., Lehnert M., Omont A.,
Riechers D.A., Baker A.J., Bendo G., Borsato E., Buat V., Butler K.,
Chartab N., Cooray A., Dye S., Eales S., Gavazzi R., Hughes D., Ivison R.,
Jones B.M., Marchetti L., Messias H., Nanni A., Negrello M.,
Perez-fournon I., Serjeant S., Urquhart S., Vlahakis C., Weiss A.,
Van Der Werf P., Yang C.
<Astron. Astrophys., 678, A26 (2023)>
=2023A&A...678A..26C 2023A&A...678A..26C (SIMBAD/NED BibCode)
ADC_Keywords: Millimetric/submm sources ; Galaxies, IR ; Redshifts ;
Photometry, millimetric/submm
Keywords: galaxies: high-redshift - galaxies: ISM - submillimeter: galaxies -
gravitational lensing: strong - radio lines: ISM
Abstract:
Using the IRAM NOrthern Extended Millimetre Array (NOEMA), we
conducted a Large Programme (z-GAL) to measure redshifts for 126
bright galaxies detected in the Herschel Astrophysical Large Area
Survey (H-ATLAS), the HerMES Large Mode Survey (HeLMS), and the
Herschel Stripe 82 (HerS) Survey. We report reliable spectroscopic
redshifts for a total of 124 of the Herschel-selected galaxies. The
redshifts are estimated from scans of the 3 and 2-mm bands (and, for
one source, the 1-mm band), covering up to 31GHz in each band, and are
based on the detection of at least two emission lines. Together with
the Pilot Programme, where 11 sources had their spectroscopic
redshifts measured, our survey has derived precise redshifts for 135
bright Herschel-selected galaxies, making it the largest sample of
high-z galaxies with robust redshifts to date. Most emission lines
detected are from 12CO (mainly from J=2-1 to 5-4), with some sources
seen in [CI] and H2O emission lines. The spectroscopic redshifts are
in the range 0.8<z<6.55 with a median value of z=2.56±0.10, centred
on the peak epoch of galaxy formation. The linewidths of the sources
are large, with a mean value for the full width at half maximum
{DELTA}V of 590±25km/s and with 35% of the sources having widths of
700km/s<{DELTA}V<1800km/s. Most of the sources are unresolved or
barely resolved on scales of ∼2 to 3" (or linear sizes of ∼15 - 25kpc,
unlensed). Some fields reveal double or multiple sources in line
emission and the underlying dust continuum and, in some cases, sources
at different redshifts. Taking these sources into account, there are,
in total, 165 individual sources with robust spectroscopic redshifts,
including lensed galaxies, binary systems, and over-densities. This
paper presents an overview of the z-GAL survey and provides the
observed properties of the emission lines, the derived spectroscopic
redshifts, and a catalogue of the entire sample. The catalogue
includes, for each source, the combined continuum and emission lines'
maps together with the spectra for each of the detected emission
lines. The data presented here will serve as a foundation for the
other z-GAL papers in this series reporting on the dust
emission, the molecular and atomic gas properties, and a detailed
analysis of the nature of the sources. Comparisons are made with other
spectroscopic surveys of high-z galaxies and future prospects,
including dedicated follow-up observations based on these redshift
measurements, are outlined.
Description:
We present an overview of a Large Programme, z-GAL, using NOEMA to
measure reliable redshifts for a sample of 126 bright
Herschel-selected galaxies. From this original sample, spectroscopic
redshifts were measured for 124 sources. Together with the z-GAL Pilot
Programme (Neri et al., 2020A&A...635A...7N 2020A&A...635A...7N,Cat. J/A+A/635/A7), where
11 sources had their spectroscopic redshifts measured, this amounts to
135 dusty, bright Herschel-selected galaxies with precise redshifts,
making it the largest sample of high-z galaxies with unambiguous
redshifts to date and more than doubling the number of
Herschel-selected galaxies with robust spectroscopic redshifts.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 102 59 z-GAL Sample: HeLMS and HerS sources
tablea2.dat 113 67 z-GAL Sample: HerBS sources
tablea3.dat 113 11 HerBS sources from the Pilot Programme
(Neri et al., 2020A&A...635A...7N 2020A&A...635A...7N,
Cat. J/A+A/635/A7)
tablea4.dat 111 16 Northern galactic plane and equatorial sources,
without spectroscopic redshift measurements,
not selected in (or dropped from) z-GAL from
the HerBS, HeLMS, and HerS catalogues
tablea5.dat 111 44 Northern galactic plane and equatorial sources
with previously available spectroscopic
redshift measurements from the HerBS, HeLMS,
and HerS catalogues
tablea6.dat 178 67 Spectroscopic redshifts and emission line
properties: HeLMS and HerS sources
tablea78.dat 158 85 Spectroscopic redshifts and emission line
properties: HerBS sources (tables A7 + A8)
tablea9.dat 137 14 Spectroscopic redshifts and emission line
properties: HerBS sources from Neri et al.
(2020A&A...635A...7N 2020A&A...635A...7N, Cat. J/A+A/635/A7)
--------------------------------------------------------------------------------
See also:
J/MNRAS/473/1751 : Herschel Bright Sources (HerBS) (Bakx+, 2018)
J/A+A/635/A7 : NOEMA redshift of bright Herschel galaxies (Neri+, 2020)
J/A+A/678/A27 : z-GAL dust continuum properties (Ismail+, 2023)
J/A+A/678/A28 : z-GAL. III. Physical properties (Berta+, 2023)
Byte-by-byte Description of file: tablea1.dat tablea2.dat tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Type [HeLMS HerBS] Type
8- 31 A24 --- Name Source name Herschel (1)
32- 40 A9 --- OName Other name
43- 44 I2 h RAh Herschel Right ascension (J2000)
46- 47 I2 min RAm Herschel Right ascension (J2000)
49- 52 F4.1 s RAs Herschel Right ascension (J2000)
54 A1 --- DE- Herschel Declination sign (J2000)
55- 56 I2 deg DEd Herschel Declination (J2000)
58- 59 I2 arcmin DEm Herschel Declination (J2000)
61- 62 I2 arcsec DEs Herschel Declination (J2000)
64- 67 F4.2 --- zphota Photometric redshift re-evaluated using the
method described by
Ivison et al. (2016ApJ...832...78I 2016ApJ...832...78I)
69- 72 F4.2 --- zphotb Photometric redshift re-evaluated using the
method described by
Pearson et al. (2013MNRAS.435.2753P 2013MNRAS.435.2753P)
74- 78 F5.1 mJy S250um Flux density Herschel at 250um
80- 82 F3.1 mJy e_S250um Flux density Herschel at 250um error
83- 88 F6.1 mJy S350um Flux density Herschel at 350um
90- 92 F3.1 mJy e_S350um Flux density Herschel at 350um error
93- 98 F6.1 mJy S500um Flux density Herschel at 500um
100-103 F4.1 mJy e_S500um Flux density Herschel at 500um error
105-109 F5.1 mJy S850um ? Flux density SCUBA-2 at 850um (2)
111-113 F3.1 mJy e_S850um ? Flux density SCUBA-2 at 850um error (2)
--------------------------------------------------------------------------------
Note (1): In table A1, The source names and Herschel flux densities are from
Nayyeri et al. (2016ApJ...823...17N 2016ApJ...823...17N)
In table A2 and A3, The source names and Herschel flux densities are
from Bakx et al. (2018MNRAS.473.1751B 2018MNRAS.473.1751B, Cat. J/MNRAS/473/1751).
Note (2): The SCUBA-2 flux densities of the HerBS sources are the revised values
from Bakx et al. (2020MNRAS.494...10B 2020MNRAS.494...10B, erratum of 2018MNRAS.473.1751B 2018MNRAS.473.1751B).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Type Type (HeLMS+ pour HeLMS and HerS sources)
8- 31 A24 --- Name Source name Herschel (1)
33- 41 A9 --- OName Other name
44- 45 I2 h RAh Herschel Right ascension (J2000)
47- 48 I2 min RAm Herschel Right ascension (J2000)
50- 53 F4.1 s RAs Herschel Right ascension (J2000)
55 A1 --- DE- Herschel Declination sign (J2000)
56- 57 I2 deg DEd Herschel Declination (J2000)
59- 60 I2 arcmin DEm Herschel Declination (J2000)
62- 63 I2 arcsec DEs Herschel Declination (J2000)
65- 69 F5.1 mJy S250um Flux density Herschel at 250um
71- 73 F3.1 mJy e_S250um Flux density Herschel at 250um error
75- 79 F5.1 mJy S350um Flux density Herschel at 350um
81- 83 F3.1 mJy e_S350um Flux density Herschel at 350um error
85- 89 F5.1 mJy S500um Flux density Herschel at 500um
91- 93 F3.1 mJy e_S500um Flux density Herschel at 500um error
95- 99 F5.1 mJy S850um ?=- Flux density SCUBA-2 at 850um (2)
101-103 F3.1 mJy e_S850um ? Flux density SCUBA-2 at 850um error (2)
104 A1 --- n_S850um [*] * for classified as non-detections
106-111 A6 --- Note Note
--------------------------------------------------------------------------------
Note (1): The source names and Herschel flux densities are from
Bakx et al. (22018MNRAS.473.1751B, Cat. J/MNRAS/473/175) and
Nayyeri et al. (2016ApJ...823...17N 2016ApJ...823...17N).
Note (2): The SCUBA-2 flux densities of the HerBS sources are the revised values
from Bakx et al. (2020MNRAS.494...10B 2020MNRAS.494...10B, erratum of 2018MNRAS.473.1751B 2018MNRAS.473.1751B).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Type Type (HeLMS+ pour HeLMS and HerS sources)
8- 31 A24 --- Name Source name Herschel (1)
33- 41 A9 --- OName Other Name
43- 44 I2 h RAh Herschel Right ascension (J2000)
46- 47 I2 min RAm Herschel Right ascension (J2000)
49- 52 F4.1 s RAs Herschel Right ascension (J2000)
54 A1 --- DE- Herschel Declination sign (J2000)
55- 56 I2 deg DEd Herschel Declination (J2000)
58- 59 I2 arcmin DEm Herschel Declination (J2000)
61- 62 I2 arcsec DEs Herschel Declination (J2000)
64- 68 F5.1 mJy S250um Flux density Herschel at 250um
70- 72 F3.1 mJy e_S250um Flux density Herschel at 250um error
74- 78 F5.1 mJy S350um Flux density Herschel at 350um
80- 82 F3.1 mJy e_S350um Flux density Herschel at 350um error
84- 88 F5.1 mJy S500um Flux density Herschel at 500um
90- 92 F3.1 mJy e_S500um Flux density Herschel at 500um error
94- 98 F5.1 mJy S850um ?=- Flux density SCUBA-2 at 850um (2)
100-102 F3.1 mJy e_S850um ? Flux density SCUBA-2 at 850um error (2)
103 A1 --- n_S850um [*] * for classified as non-detections
105-110 F6.4 --- zsp Spectroscopic redshift (3)
111 A1 --- n_zsp [*a] Note on zsp (4)
--------------------------------------------------------------------------------
Note (1): The source names and Herschel flux densities are from
Bakx et al. (22018MNRAS.473.1751B, Cat. J/MNRAS/473/175) and
Nayyeri et al. (2016ApJ...823...17N 2016ApJ...823...17N).
Note (2): The SCUBA-2 flux densities of the HerBS sources are the revised values
from Bakx et al. (2020MNRAS.494...10B 2020MNRAS.494...10B, erratum of 2018MNRAS.473.1751B 2018MNRAS.473.1751B).
Note (3): The references to the spectroscopic redshifts measurements are given
in Bakx et al. (22018MNRAS.473.1751B) and Nayyeri et al. (2016ApJ...823...17N 2016ApJ...823...17N);
for the HeLMS and HerS sources, the zspec values have been udpated for the
sources included in Riechers et al. (2021ApJ...913..141R 2021ApJ...913..141R) and Maresca et al.
(2022MNRAS.512.2426M 2022MNRAS.512.2426M) (and references therein);
for HerBS-52 and HerBS-64, the spectroscopic redshifts are from
Bakx et al. (2020MNRAS.496.2372B 2020MNRAS.496.2372B).
Note (4): Note os zsp as follows:
* = Spectroscopic redshifts derived from on a single line detection and are
therefore considered tentative
a = spectroscopic redshift of HerS-4 was measured with the LMT
(A. Baker, priv. comm.)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea[679]*.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- Type Type (HeLMS, HerBS or HerS)
7- 19 A13 --- Source Source name
21- 22 I2 h RAh Observed Right ascension (J2000)
24- 25 I2 min RAm Observed Right ascension (J2000)
27- 31 F5.2 s RAs Observed Right ascension (J2000)
33 A1 --- DE- Observed Declination sign (J2000)
34- 35 I2 deg DEd Observed Declination (J2000)
37- 38 I2 arcmin DEm Observed Declination (J2000)
40- 43 F4.1 arcsec DEs Observed Declination (J2000)
45- 50 F6.4 --- zsp Spectroscopic redshift
52- 57 F6.4 --- e_zsp Spectroscopic redshift error derived from
the simultaneous Gaussian fits to the
line profiles
58 A1 --- n_zsp [*] Note on zsp (1)
59- 62 I4 km/s DeltaV Mean linewidths (FWHM) weighted by the peak
intensities of the detected CO emission
lines
64- 66 I3 km/s e_DeltaV DeltaV error
67 A1 --- n_DeltaV [*] * for emission lines fitted with
double Gaussians
69- 80 A12 --- Line1 Emission line 1
81- 85 F5.2 Jy.km/s Line1Flux Flux in emission line 1
87- 90 F4.2 Jy.km/s e_Line1Flux Flux in emission line 1 error
91 A1 --- n_Line1Flux [*] Note on Line1Flux (1)
92-103 A12 --- Line2 Emission line 2
104 A1 -- l_Line2Flux Limit flag on Line2Flux
105-109 F5.2 Jy.km/s Line2Flux ? Flux in emission line 2
111-114 F4.2 Jy.km/s e_Line2Flux ? Flux in emission line 2 error
116-128 A13 --- Line3 Emission line 3
130-133 F4.2 Jy.km/s Line3Flux ? Flux in emission line 3
135-138 F4.2 Jy.km/s e_Line3Flux ? Flux in emission line 3 error
140-148 A9 --- Line4 Emission line 4
150-153 F4.2 Jy.km/s Line4Flux ? Flux in emission line 4
155-158 F4.2 Jy.km/s e_Line4Flux ? Flux in emission line 4 error
160-168 A9 --- Line5 Emission line 5
170-173 F4.2 Jy.km/s Line5Flux ? Flux in emission line 5
175-178 F4.2 Jy.km/s e_Line5Flux ? Flux in emission line 5 error
--------------------------------------------------------------------------------
Note (1): * for redshifts and line identifications that are not robust
(for HerS-18 W, HerS-19 SE & W, HerBS-82). Further details about the line
fitting procedure and the derivation of zspec are provided in Appendix A.1.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Ismail et al., Paper II 2023A&A...678A..27I 2023A&A...678A..27I, Cat. J/A+A/678/A27
Berta et al., Paper III 2023A&A...678A..28B 2023A&A...678A..28B, Cat. J/A+A/678/A28
(End) Patricia Vannier [CDS] 27-Nov-2023