J/MNRAS/471/1910 [OII] nebular emission from MgII absorbers (Joshi+, 2017)
[O II] nebular emission from Mg II absorbers:
star formation associated with the absorbing gas.
Joshi R., Srianand R., Petitjean P., Noterdaeme P.
<Mon. Not. R. Astron. Soc., 471, 1910-1925 (2017)>
=2017MNRAS.471.1910J 2017MNRAS.471.1910J (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Equivalent widths ; Spectroscopy
Keywords: galaxies: evolution - galaxies: ISM - quasars: absorption lines -
galaxies: star formation - cosmology: observations
Abstract:
We present nebular emission associated with 198 strong Mg II absorbers
at 0.35≤z≤1.1 in the fibre spectra of quasars from the Sloan Digital
Sky Survey. Measured [OII] luminosities (L[OII]) are typical of
sub-L* galaxies with derived star formation rate (uncorrected for
fibre losses and dust reddening) in the range of 0.5-20M☉/yr.
Typically less than ∼3 per cent of the MgII systems with rest
equivalent width, W2796≥2Å, show L[OII]≥0.3L*[OII]. The
detection rate is found to increase with increasing W2796 and z. No
significant correlation is found between W2796 and L[OII] even
when we restrict the samples to narrow z ranges. A strong correlation
is seen between L[OII] and z. While this is expected from the
luminosity evolution of galaxies, we show that finite fibre size plays
a very crucial role in this correlation. The measured nebular line
ratios (like [OIII]/[OII] and [OIII]/H β) and their z evolution
are consistent with those of galaxies detected in deep surveys. Based
on the median stacked spectra, we infer the average metallicity
(logZ∼8.3), ionization parameter (logq∼7.5) and stellar mass (log
(M/M☉)∼9.3). The MgII systems with nebular emission typically
have W2796≥2Å, MgII doublet ratio close to 1 and
W(FeIIλ2600)/W2796∼0.5 as often seen in damped Ly α and
21-cm absorbers at these redshifts. This is the biggest reported
sample of [OII] emission from MgII absorbers at low-impact parameters
ideally suited for probing various feedback processes at play in z≤1
galaxies.
Description:
We use the compilation of MgII systems from the expanded-version of
JHU-SDSS Metal Absorption Line Catalog
(http://www.pha.jhu.edu/~gz323/Site/, Zhu & Menard,
2013ApJ...770..130Z 2013ApJ...770..130Z), generated from the SDSS-DR7 and SDSS-DR12.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 132 212 Catalog of MgII absorber galaxies with nebular
emission
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See also:
http://skyserver.sdss.org : SDSS Home Page
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 24 A24 --- Name Name of the source, SDSS-JHHMMSS.ss+DDMMSS.s or
BOSS-JHHMMSS.ss+DDMMSS
25 A1 --- n_Name [*] Note on Name (1)
28- 31 I4 --- Plate SDSS Plate
33- 37 I5 --- MJD SDSS MJD
39- 42 I4 --- Fiber SDSS Fiber
47- 52 F6.4 --- ZQSO Quasar Emission Redshift
57- 62 F6.4 --- Zabs Absorber Redshift
67- 72 F6.2 10+33W L[OII] Lumimosity of [OII](3727,3729) line (2)
77- 81 F5.2 10+33W e_L[OII] Error on [OII] line luminosity
84 A1 --- l_L[OIII] Limit flag on L[OIII]
85- 90 F6.2 10+33W L[OIII] Lumimosity of [OIII]5008 line (2)
94- 98 F5.2 10+33W e_L[OIII] ? Error on OIII line luminosity
102 A1 --- l_LHbeta Limit flag on LHbeta
103-108 F6.2 10+33W LHbeta Lumimosity of Hβ4862 line (2)
112-116 F5.2 10+33W e_LHbeta ? Error on Hbeta line luminosity
123-126 F4.2 0.1nm EWMgII Equivalent Width of MgII2796
129-132 F4.2 0.1nm e_EWMgII Error on Equivalent Width of MgII2796
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Note (1): * for the systems with repeat observations in SDSS-DR7 or SDSS-DR12.
Note (2): The line luminosity is given in units of 1040erg/s.
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Acknowledgements:
Joshi Ravi, rvjoshirv(at)gmail.com
(End) Patricia Vannier [CDS] 24-May-2020