O II nebular emission from Mg II absorbers: Star formation associated
with the absorbing gas
R. Joshi, R. Srianand, P. Petitjean, and P. Noterdaeme. (2017)cite arxiv:1706.03075Comment: 18 Pages, 18 Figures, 4 Tables (Accepted for the Publication in MNRAS main-journal).
Abstract
We present nebular emission associated with 198 strong Mg II absorbers at
0.35 $z łe$ 1.1 in the fibre spectra of quasars from the Sloan Digital Sky
Survey. Measured O II luminosities (L$_O II$) are typical of
sub-L$^\star$ galaxies with derived star formation rate (uncorrected for
fibre losses and dust reddening) in the range of 0.5-20 $M_ødot\
yr^-1$. Typically less than $\sim$ 3% of the Mg II systems with rest
equivalent width, $W_2796$ $\ge$ 2 \AA, show L$_O II 0.3$
L$^\star_O II$. The detection rate is found to increase with increasing
$W_2796$ and $z$. No significant correlation is found between $W_2796$ and
L$_O II$ even when we restrict the samples to narrow $z$-ranges. A strong
correlation is seen between L$_O II$ and $z$. While this is expected from
the luminosity evolution of galaxies, we show finite fibre size plays a very
crucial role in this correlation. The measured nebular line ratios (like O
III/O II and O III/H$\beta$) 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 (log Z $\sim$8.3), ionization
parameter (log $q$ $\sim$7.5) and stellar mass (log (M/M$_ødot$)$\sim$9.3).
The Mg II systems with nebular emission typically have $W_2796$ $2$ \AA,
Mg II doublet ratio close to 1 and W(Fe II$łambda$2600)/$W_2796$ $0.5$
as often seen in damped Ly$\alpha$ and 21-cm absorbers at these redshifts. This
is the biggest reported sample of O II emission from Mg II absorbers at low
impact parameters ideally suited for probing various feedback processes at play
in $z1$ galaxies.
Description
[1706.03075] [O II] nebular emission from Mg II absorbers: Star formation associated with the absorbing gas
%0 Generic
%1 joshi2017nebular
%A Joshi, Ravi
%A Srianand, Raghunathan
%A Petitjean, Patrick
%A Noterdaeme, Pasquier
%D 2017
%K MgII [OII] emission low-z
%T O II nebular emission from Mg II absorbers: Star formation associated
with the absorbing gas
%U http://arxiv.org/abs/1706.03075
%X We present nebular emission associated with 198 strong Mg II absorbers at
0.35 $z łe$ 1.1 in the fibre spectra of quasars from the Sloan Digital Sky
Survey. Measured O II luminosities (L$_O II$) are typical of
sub-L$^\star$ galaxies with derived star formation rate (uncorrected for
fibre losses and dust reddening) in the range of 0.5-20 $M_ødot\
yr^-1$. Typically less than $\sim$ 3% of the Mg II systems with rest
equivalent width, $W_2796$ $\ge$ 2 \AA, show L$_O II 0.3$
L$^\star_O II$. The detection rate is found to increase with increasing
$W_2796$ and $z$. No significant correlation is found between $W_2796$ and
L$_O II$ even when we restrict the samples to narrow $z$-ranges. A strong
correlation is seen between L$_O II$ and $z$. While this is expected from
the luminosity evolution of galaxies, we show finite fibre size plays a very
crucial role in this correlation. The measured nebular line ratios (like O
III/O II and O III/H$\beta$) 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 (log Z $\sim$8.3), ionization
parameter (log $q$ $\sim$7.5) and stellar mass (log (M/M$_ødot$)$\sim$9.3).
The Mg II systems with nebular emission typically have $W_2796$ $2$ \AA,
Mg II doublet ratio close to 1 and W(Fe II$łambda$2600)/$W_2796$ $0.5$
as often seen in damped Ly$\alpha$ and 21-cm absorbers at these redshifts. This
is the biggest reported sample of O II emission from Mg II absorbers at low
impact parameters ideally suited for probing various feedback processes at play
in $z1$ galaxies.
@misc{joshi2017nebular,
abstract = {We present nebular emission associated with 198 strong Mg II absorbers at
0.35 $\le z \le$ 1.1 in the fibre spectra of quasars from the Sloan Digital Sky
Survey. Measured [O II] luminosities (L$_{[O II]}$) are typical of
sub-L$^{\star}$ galaxies with derived star formation rate (uncorrected for
fibre losses and dust reddening) in the range of 0.5-20 ${\rm M_\odot\
yr^{-1}}$. Typically less than $\sim$ 3% of the Mg II systems with rest
equivalent width, $W_{2796}$ $\ge$ 2 \AA, show L$_{[O II]} \ge 0.3$
L$^{\star}_{[O II]}$. The detection rate is found to increase with increasing
$W_{2796}$ and $z$. No significant correlation is found between $W_{2796}$ and
L$_{[O II]}$ even when we restrict the samples to narrow $z$-ranges. A strong
correlation is seen between L$_{[O II]}$ and $z$. While this is expected from
the luminosity evolution of galaxies, we show finite fibre size plays a very
crucial role in this correlation. The measured nebular line ratios (like [O
III]/[O II] and [O III]/H$\beta$) 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 (log Z $\sim$8.3), ionization
parameter (log $q$ $\sim$7.5) and stellar mass (log (M/M$_\odot$)$\sim$9.3).
The Mg II systems with nebular emission typically have $W_{2796}$ $\ge 2$ \AA,
Mg II doublet ratio close to 1 and W(Fe II$\lambda$2600)/$W_{2796}$ $\sim 0.5$
as often seen in damped Ly$\alpha$ and 21-cm absorbers at these redshifts. This
is the biggest reported sample of [O II] emission from Mg II absorbers at low
impact parameters ideally suited for probing various feedback processes at play
in $z\le 1$ galaxies.},
added-at = {2017-06-13T10:04:02.000+0200},
author = {Joshi, Ravi and Srianand, Raghunathan and Petitjean, Patrick and Noterdaeme, Pasquier},
biburl = {https://www.bibsonomy.org/bibtex/2a7895c49ce8daa66e4a9e58d102a55d6/miki},
description = {[1706.03075] [O II] nebular emission from Mg II absorbers: Star formation associated with the absorbing gas},
interhash = {c961e3af08b0323c2bb63e60f1ca42b1},
intrahash = {a7895c49ce8daa66e4a9e58d102a55d6},
keywords = {MgII [OII] emission low-z},
note = {cite arxiv:1706.03075Comment: 18 Pages, 18 Figures, 4 Tables (Accepted for the Publication in MNRAS main-journal)},
timestamp = {2017-06-13T10:04:02.000+0200},
title = {[O II] nebular emission from Mg II absorbers: Star formation associated
with the absorbing gas},
url = {http://arxiv.org/abs/1706.03075},
year = 2017
}