[O ii] nebular emission from Mg ii absorbers: star formation associated with the absorbing gas

Joshi, Ravi; Srianand, R.; Petitjean, P.; Noterdaeme, P.

doi:10.1093/mnras/stx1499

Cited by 14 publications

(20 citation statements)

References 76 publications

(105 reference statements)

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“…From the visual inspection, we confirm the detection of NEL in the troughs of 155 eclipsing DLAs from our statistical sample. We note that the possibility that these NELs could be the [O ii] and/or [O iii] emission from some intervening low redshift galaxies is very small (Noterdaeme, Srianand & Mohan, 2010;Joshi et al, 2017). However, we still checked this possibility for the strongest Lyα NELs in our sample and found that none of them could be attributed to the [O ii] and/or [O iii] emission from intervening galaxies.…”

Section: Zero-level Correction and Nel Detectionmentioning

confidence: 65%

Eclipsing damped Ly α systems in the Sloan Digital Sky Survey Data Release 12★

Fathivavsari

Petitjean

Jamialahmadi

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We present the results of our automatic search for proximate damped Lyα absorption (PDLA) systems in the quasar spectra from the Sloan Digital Sky Survey Data Release 12. We constrain our search to those PDLAs lying within 1500 km s −1 from the quasar to make sure that the broad DLA absorption trough masks most of the strong Lyα emission from the broad line region (BLR) of the quasar. When the Lyα emission from the BLR is blocked by these so-called eclipsing DLAs, narrow Lyα emission from the host galaxy could be revealed as a narrow emission line (NEL) in the DLA trough. We define a statistical sample of 399 eclipsing DLAs with log N (H i) ≥ 21.10. We divide our statistical sample into three subsamples based on the strength of the NEL detected in the DLA trough. By studying the stacked spectra of these subsamples, we found that absorption from high ionization species are stronger in DLAs with stronger NEL in their absorption core. Moreover, absorption from the excited states of species like Si ii are also stronger in DLAs with stronger NEL. We also found no correlation between the luminosity of the Lyα NEL and the quasar luminosity. These observations are consistent with a scenario in which the DLAs with stronger NEL are denser and physically closer to the quasar. We propose that these eclipsing DLAs could be the product of the interaction between infalling and outflowing gas. High resolution spectroscopic observation would be needed to shed some light on the nature of these eclipsing DLAs.

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Section: Zero-level Correction and Nel Detectionmentioning

confidence: 65%

Eclipsing damped Ly α systems in the Sloan Digital Sky Survey Data Release 12★

Fathivavsari

Petitjean

Jamialahmadi

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…In the following analysis, we use the systemic redshift of G0 as reference for the analysis of the absorption profile plotted in velocity (see appendix A) simply because it has the smallest impact parameter to the quasar of all objects spectroscopically detected in the field. In essence, this system is like the "Galaxies with background QSOs" searches which have found quasars shining through low redshift, foreground galaxies at small impact parameters (<10 kpc) within the SDSS fibers (York et al 2012;Straka et al 2013;Straka et al 2015;Joshi et al 2017). These, together with recent findings of low impact parameter objects in high spatial resolution HST imaging (i.e.…”

Section: Analysis and Resultsmentioning

confidence: 80%

Multiphase circumgalactic medium probed with MUSE and ALMA

Péroux

Zwaan

Klitsch

et al. 2019

Monthly Notices of the Royal Astronomical Society

104

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Galaxy halos appear to be missing a large fraction of their baryons, most probably hiding in the circumgalactic medium (CGM), a diffuse component within the dark matter halo that extends far from the inner regions of the galaxies. A powerful tool to study the CGM gas is offered by absorption lines in the spectra of background quasars. Here, we present optical (MUSE) and mm (ALMA) observations of the field of the quasar Q1130−1449 which includes a log [N (HI)/cm −2 ]=21.71±0.07 absorber at z=0.313. Ground-based VLT/MUSE 3D spectroscopy shows 11 galaxies at the redshift of the absorber down to a limiting SFR>0.01 M yr −1 (covering emission lines of [O ii], Hβ, [O iii], [N ii] and Hα), 7 of which are new discoveries. In particular, we report a new emitter with a smaller impact parameter to the quasar line-of-sight (b=10.6 kpc) than the galaxies detected so far. Three of the objects are also detected in CO(1-0) in our ALMA observations indicating long depletion timescales for the molecular gas and kinematics consistent with the ionised gas. We infer from dedicated numerical cosmological RAMSES zoom-in simulations that the physical properties of these objects qualitatively resemble a small group environment, possibly part of a filamentary structure. Based on metallicity and velocity arguments, we conclude that the neutral gas traced in absorption is only partly related to these emitting galaxies while a larger fraction is likely the signature of gas with surface brightness almost four orders of magnitude fainter that current detection limits. Together, these findings challenge a picture where strong-N (H I) quasar absorbers are associated with a single bright galaxy and favour a scenario where the H i gas probed in absorption is related to far more complex galaxy structures.

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“…1Å (see also, Gupta et al 2012). Recently, we have detected 198 [O ii] emitting galaxies associated with strong Mg ii absorbers in the spectra of SDSS (Joshi et al 2017b, hereinafter refer as Paper 1). We have found that the Mg ii absorbers detected in [O ii] nebular emission (with L [O II] > 2 × 10 40 erg s −1 ) typically have W2796 1Å, Mg ii doublet ratio (DR = W Mg IIλ2796 /W Mg IIλ2803 ) close to unity and R 0.5.…”

Section: Introductionmentioning

confidence: 99%

“…Rahmani et al (2010) have stacked the damped-Lyα absorbers (DLA) with log N (H i) 20.3 to detect the average Lyα emission and set an upper limit on the contribution of DLA galaxies to the cosmic SFRD of ∼ 0.13 M⊙ yr −1 Mpc −3 at z ∼ 3 (see also, Noterdaeme et al 2014;Joshi et al 2017a). However, as mentioned above physical parameters derived from fibre spectra suffer from effect of fibre losses and one has to be mindful of this while interpreting these results (López & Chen 2012;Joshi et al 2017b).…”

Section: Introductionmentioning

confidence: 99%

Average [O II] nebular emission associated with Mg II absorbers: dependence on Fe II absorption

Joshi

Srianand

Petitjean

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We investigate the effect of Fe ii equivalent width (W 2600 ) and fibre size on the average luminosity of [O ii]λλ3727,3729 nebular emission associated with Mg ii absorbers (at 0.55 z 1.3) in the composite spectra of quasars obtained with 3 and 2 arcsec fibres in the Sloan Digital Sky Survey. We confirm the presence of strong correlations between [O ii] luminosity (L [O II] ) and equivalent width (W 2796 ) and redshift of Mg ii absorbers. However, we show L [O II] and average luminosity surface density suffers from fibre size effects. More importantly, for a given fibre size the average L [O II] strongly depends on the equivalent width of Fe ii absorption lines and found to be higher for Mg ii absorbers with R ≡ W 2600 /W 2796 0.5. In fact, we show the observed strong correlations of L [O II] with W 2796 and z of Mg ii absorbers are mainly driven by such systems. Direct [O ii] detections also confirm the link between L [O II]and R. Therefore, one has to pay attention to the fibre losses and dependence of redshift evolution of Mg ii absorbers on W 2600 before using them as a luminosity unbiased probe of global star formation rate density. We show that the [O ii] nebular emission detected in the stacked spectrum is not dominated by few direct detections (i.e., detections 3σ significant level). On an average the systems with R 0.5 and W 2796 2Å are more reddened, showing colour excess E(B − V ) ∼ 0.02, with respect to the systems with R < 0.5 and most likely traces the high H i column density systems.

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[O ii] nebular emission from Mg ii absorbers: star formation associated with the absorbing gas

Cited by 14 publications

References 76 publications

Eclipsing damped Ly α systems in the Sloan Digital Sky Survey Data Release 12★

Eclipsing damped Ly α systems in the Sloan Digital Sky Survey Data Release 12★

Multiphase circumgalactic medium probed with MUSE and ALMA

Average [O II] nebular emission associated with Mg II absorbers: dependence on Fe II absorption

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