J/MNRAS/449/3263 Extended galaxy halo gas through HI and OVI (Johnson+, 2015)
On the possible environmental effect in distributing heavy elements beyond
individual gaseous haloes.
Johnson S.D., Chen H.-W., Mulchaey J.S.
<Mon. Not. R. Astron. Soc., 449, 3263-3273 (2015)>
=2015MNRAS.449.3263J 2015MNRAS.449.3263J (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Galaxies, spectra
Keywords: galaxies: haloes - galaxies: interactions - intergalactic medium -
quasars: absorption lines
Abstract:
We present a study of extended galaxy halo gas through HI and OVI
absorption over two decades in projected distance at z∼0.2. The study
is based on a sample of 95 galaxies from a highly complete (>80
percent) survey of faint galaxies (L>0.1L*) with archival quasar
absorption spectra and 53 galaxies from the literature. A clear
anticorrelation is found between HI (OVI) column density and virial
radius normalized projected distance, d/Rh. Strong HI (OVI) absorption
systems with column densities greater than 1014.0 (1013.5)cm-2
are found for 48 of 54 (36 of 42) galaxies at d<Rh indicating a mean
covering fraction of <κHI≥0.89 (<κOVI≥0.86). OVI
absorbers are found at d∼Rh, beyond the extent observed for lower
ionization species. At d/Rh=1-3 strong HI (OVI) absorption systems are
found for only 7 of 43 (5 of 34) galaxies (<κHI≥0.16 and
<κOVI≥0.15). Beyond d=3Rh, the HI and OVI covering fractions
decrease to levels consistent with coincidental systems. The high
completeness of the galaxy survey enables an investigation of
environmental dependence of extended gas properties. Galaxies with
nearby neighbours exhibit a modest increase in Ovi covering fraction
at d>Rh compared to isolated galaxies (<κOVI∼0.13 versus 0.04)
but no excess HI absorption. These findings suggest that environmental
effects play a role in distributing heavy elements beyond the enriched
gaseous haloes of individual galaxies. Finally, we find that
differential HI and OVI absorption between early- and late-type
galaxies continues from d<Rh to d∼3Rh.
Description:
To assemble the eCGM galaxy sample, we combined our own
absorption-blind survey data targeting galaxies of rAB<23mag in the
fields of HE 0226-4110, PKS 0405-123, LBQS 1435-0134, and
PG 1522+101 with spectroscopic galaxies in the SDSS Data Release 10
(DR10; York et al., 2000AJ....120.1579Y 2000AJ....120.1579Y; Ahn et al.,
2014ApJS..211...17A 2014ApJS..211...17A).
The HE 0226-4110, PKS 0405-123, LBQS 1435-0134, and PG 1522+101
fields were selected because of the high completeness levels
(80 per cent) achieved by our surveys for galaxies as faint as
L=0.1L* at z<0.4 and d<500kpc. At smaller projected distances of d=100
and 200kpc, the survey completeness increases to 100 and
90 per cent, respectively (see fig. 2 of Johnson, Chen & Mulchaey,
2013, Cat. J/MNRAS/434/1765). We included SDSS galaxies to increase
the number of eCGM sample members of logM*/M☉>11. The resulting
galaxy sample is summarized in Table 1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 108 148 Summary of galaxy and absorber properties
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See also:
J/MNRAS/434/1765 : Catalog of galaxies around PKS 0405-123 (Johnson+, 2013)
http://www.sdss3.org : SDSS-III website
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Galaxy sightline name
16- 17 I2 h RAh Right ascension (J2000)
19- 20 I2 min RAm Right ascension (J2000)
22- 26 F5.2 s RAs Right ascension (J2000)
28 A1 --- DE- Declination sign (J2000)
29- 30 I2 deg DEd Declination (J2000)
32- 33 I2 arcmin DEm Declination (J2000)
35- 38 F4.1 arcsec DEs Declination (J2000)
40- 45 F6.4 --- zgal Galaxy redshift
47- 50 F4.1 [Msun] logM* Stellar mass
52- 56 A5 --- Class [Early Late] Classification (1)
58- 59 A2 --- Env [I NI A] Environment class (2)
61- 69 A9 --- Survey Survey
71- 73 I3 kpc d Distance
75- 78 F4.1 --- d/Rh Virial radius normalized projected distance
80 A1 --- l_logNHI Limit flag on logNHI
81- 85 F5.2 [cm-2] logNHI ?=-1 HI column density
87- 90 F4.2 [cm-2] e_logNHI ? rms uncertainty on logNHI
91 A1 --- --- [-]
92- 96 F5.2 [cm-2] logNHIu ? Upper value of logNHI when interval
98 A1 --- l_logNHOVI Limit flag on logNHOVI
99-103 F5.2 [cm-2] logNHOVI ?=-1 OIV column density (3)
105-108 F4.2 [cm-2] e_logNHOVI ? rms uncertainty on logNHOVI
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Note (1): Galaxy classification as follows:
Early = early-type, absorption-line dominated galaxies
Late = late-type, emission-line dominated galaxies
Note (2): Galaxy environment class defined as follows:
I = isolated
NI = non-isolated
A = ambiguous cases
Note (3): Total column density measured in the COS sightline within
ΔV=±300km/s of the galaxy systemic redshift.
In cases where OVI or HI column densities cannot be measured due to
contamination, the value is set to -1.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 10-Dec-2015