J/ApJS/237/11 Gal. redshift survey near HST/COS AGN sight lines (Keeney+, 2018)
A galaxy redshift survey near HST/COS AGN sight lines.
Keeney B.A., Stocke J.T., Pratt C.T., Davis J.D., Syphers D., Danforth C.W.,
Shull J.M., Froning C.S., Green J.C., Penton S.V., Savage B.D.
<Astrophys. J. Suppl. Ser., 237, 11 (2018)>
=2018ApJS..237...11K 2018ApJS..237...11K
ADC_Keywords: Galaxies, spectra; Redshifts; Photometry, SDSS;
Intergalactic medium; Active gal. nuclei
Keywords: galaxies: distances and redshifts ; intergalactic medium ; surveys
Abstract:
To establish the connection between galaxies and UV-detected
absorption systems in the local universe, a deep (g≤20) and wide
(∼20' radius) galaxy redshift survey is presented around 47 sight
lines to UV-bright AGNs observed by the Cosmic Origins Spectrograph
(COS). Specific COS science team papers have used this survey to
connect absorbers to galaxies, groups of galaxies, and large-scale
structures, including voids. Here we present the technical details of
the survey and the basic measurements required for its use, including
redshifts for individual galaxies and uncertainties determined
collectively by spectral class (emission-line, absorption-line, and
composite spectra) and completeness for each sight line as a function
of impact parameter and magnitude. For most of these sight lines, the
design criteria of >90% completeness over a >1Mpc region down to
≲0.1L* luminosities at z≤0.1 allows a plausible association between
low-z absorbers and individual galaxies. Lyα covering fractions
are computed to approximate the star-forming and passive galaxy
populations using the spectral classes above. In agreement with
previous results, the covering fraction of star-forming galaxies with
L≥0.3L* is consistent with unity inside one virial radius and
declines slowly to >50% at four virial radii. On the other hand,
passive galaxies have lower covering fractions (∼60%) and a shallower
decline with impact parameter, suggesting that their gaseous halos are
patchy but have a larger scale-length than star-forming galaxies.
Description:
The COS GTO galaxy redshift survey was designed to obtain redshifts
for all galaxies with g<20 that are within 20' of each of the 40 AGN
sight lines targeted by the HST/COS GTO team. We successfully observed
galaxies near 38 of these sight lines.
When SDSS imaging was unavailable (primarily in the southern
hemisphere) we obtained our own images of the sight lines using the
MOSAIC imagers of the Blanco 4m telescope at Cerro Tololo
Inter-American Observatory (40'x40' field of view) in 2008 Sep 21-23
and the WIYN 0.9m telescope at Kitt Peak National Observatory (60'x60'
field of view) in 2008 Feb 9 and 2009 Feb 22.
Multi-object spectroscopy (MOS) for this COS GTO galaxy redshift
survey was performed with the HYDRA spectrograph on the WIYN 3.5m
telescope at Kitt Peak National Observatory (R∼1200) in 2014 Feb &
June, 2013 Feb-Mar, 2012 Mar-Apr, 2011 Apr, 2010 Feb & Apr, 2009 Feb
and 2008 Feb or the AAΩ spectrograph on the 3.9m Anglo-Australian
Telescope at Siding Springs Observatory (R∼1300) in 2013 Sep and 2012 Aug.
The galaxy group survey was designed to support HST/COS observations
of AGNs that probe SDSS-selected galaxy groups
(Stocke+ 2017ApJ...838...37S 2017ApJ...838...37S). The 10 sight lines observed as part of
this study are listed in Table 4.
MOS for this galaxy group survey was performed with WIYN/HYDRA
(R∼1200) in 2016 and 2017 March and MMT/Hectospec (R∼1000) in 2016
May, June and 2017 Feb.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 64 38 COS GTO sight lines surveyed
table4.dat 64 10 SDSS group sight lines surveyed
table6.dat 120 8886 Galaxy redshift measurements
table9.dat 48 240 Completeness table
--------------------------------------------------------------------------------
See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
J/ApJ/559/654 : Lyα absorption systems. V. (Chen+, 2001)
J/ApJ/701/1219 : Galaxy survey in 3 QSO fields (Chen+, 2009)
J/ApJS/182/378 : HI and OVI absorbers in nearby Universe (Wakker+, 2009)
J/ApJS/193/28 : Galaxy survey around 20 UV-bright quasars (Prochaska+, 2011)
J/MNRAS/434/1765 : Catalog of galaxies around PKS 0405-123 (Johnson+, 2013)
J/ApJ/791/128 : Basic data for spiral-rich group members (Stocke+, 2014)
J/MNRAS/445/2061 : Absorption in multiphase circumgal. medium (Liang+, 2014)
J/ApJ/815/91 : z<0.16 CIV absorbers from HST/COS spectra (Burchett+, 2015)
J/ApJS/219/8 : SFR for WISE + SDSS spectroscopic galaxies (Chang+, 2015)
J/ApJ/817/111 : HST/COS survey of z<0.9 AGNs. I. (Danforth+, 2016)
J/ApJS/230/6 : HST-COS & -STIS absorption-line spec. II. (Keeney+, 2017)
Byte-by-byte Description of file: table[14].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Name Sight line name
18 A1 --- f_Name [b] Flag on Name (1)
20- 21 I2 h RAh Hour of declination (J2000)
23- 24 I2 min RAm Minute of declination (J2000)
26- 30 F5.2 s RAs Second of declination (J2000)
32 A1 --- DE- Sign of declination (J2000)
33- 34 I2 deg DEd Degree of declination (J2000)
36- 37 I2 arcmin DEm Arcminute of declination (J2000)
39- 42 F4.1 arcsec DEs Arcsecond of declination (J2000)
44- 48 F5.3 --- zem [0.03/1.1] Emission redshift (2)
50- 55 F6.4 mag E(B-V) [0.004/0.2] Color excess (3)
57- 64 A8 --- Abbrev Abbreviated name used in galaxy identifier in
Table 6
--------------------------------------------------------------------------------
Note (1):
b = This sight line was never observed by HST/COS, but we include the
measured galaxy redshifts for legacy value.
Note (2): The emission-line redshift of the QSO as listed in the
NASA Extragalactic Database (NED), except for HE 0435-5304, whose
redshift was measured from its COS spectrum (Stocke+ 2013ApJ...763..148S 2013ApJ...763..148S).
Note (3): Color excesses along the line of sight as measured by
Schlafly & Finkbeiner (2011ApJ...737..103S 2011ApJ...737..103S).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- Name Galaxy identifier
20- 29 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
31- 40 F10.6 deg DEdeg Declination in decimal degrees (J2000)
42- 48 F7.5 --- z [0/1] Galaxy spectroscopic redshift
50- 56 F7.5 --- e_z [3e-05/1] Uncertainty in z
58- 61 F4.1 mag gmag [13.4/28] SDSS g band apparent AB magnitude
63- 66 F4.1 mag rmag [13/30.5] SDSS r band apparent AB magnitude
68- 71 F4.1 mag imag [12.3/30.5] SDSS i band apparent AB magnitude
73- 82 F10.6 Lsun Lum [3e-05/230]?=-9.9 Rest-frame g-band luminosity
84- 88 F5.1 kpc Rvir [31.4/843.3]?=-9.9 Virial radius
90- 94 F5.2 [Msun] logMh [9.2/13.6]?=-9.9 log halo mass
96-100 F5.2 [Msun] logM* [4.2/12.8]?=-9.9 log stellar mass
102-108 F7.1 kpc rho [0/12923]?=-9.9 Impact parameter between
the galaxy and AGN sight-line positions
110-111 I2 --- Flag [-2/3]? Absorption flag (1)
113-120 A8 --- Abbrev Abbreviated name of the sight line as used in
Tables 1 and 4; column added by CDS
--------------------------------------------------------------------------------
Note (1): Flag as follows:
-2 = no COS spectrum available;
-1 = object has z<0.001 and is likely a star;
0 = galaxy is not within 1000km/s of an absorber;
1 = galaxy is within 1000km/s of an absorber but is not the closest galaxy;
2 = galaxy is closest in this Table to an absorber, but a closer galaxy
is known from SDSS or other sources;
3 = closest known galaxy to an absorber.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Name Sight line identifier
19- 25 A7 --- gmag SDSS apparent g band magnitude bin
27- 30 A4 --- Rinf5 Completeness within 5 arcminutes R:≤5' (1)
32- 36 A5 --- R5-10 Completeness between 5 and 10 arcminutes (1)
38- 42 A5 --- R10-15 Completeness between 10 and 15 arcminutes (1)
44- 48 A5 --- R15-20 Completeness between 15 and 20 arcminutes (1)
--------------------------------------------------------------------------------
Note (1): The fractional completion (i.e., the number of galaxies in a given
bin with redshift determinations divided by the number of targeted
galaxies in that bin).
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 03-Sep-2018