scholarly journals On the kinematics of neutral gas in GRB host galaxies

2015 ◽  
Vol 11 (A29B) ◽  
pp. 263-263
Author(s):  
M. Arabsalmani ◽  
P. Møller ◽  
W. Freudling ◽  
T. Zafar ◽  
J. P. U. Fynbo ◽  
...  

AbstractWe analyze a sample of 20 absorption systems intrinsic to long duration GRB host galaxies at z > 2 forwhich the metallicities are known. We compare the relation between the metallicity and cold gas velocity width for thissample to that of the Damped Lyman-alpha systems (DLAs) in the sight-lines of quasars (QSOs), and find completeagreement. We then compare the redshift evolution of the velocity-metallicity relation of our sample to that of QSODLAsand find that also GRB hosts favour a late onset of this evolution, around a redshift of ~2.6. We compute predicted stellar masses for the GRB host galaxies using the prescription determined from QSO-DLAsamples and compare the measured stellar masses for the four hosts where stellar masses have been determinedfrom SED fits. We find excellent agreement and conclude that, on basis of all available data and tests, long durationGRB-DLA hosts and intervening QSO-DLAs are consistent with being drawn from the same underlying population.

Science ◽  
2017 ◽  
Vol 355 (6331) ◽  
pp. 1285-1288 ◽  
Author(s):  
Marcel Neeleman ◽  
Nissim Kanekar ◽  
J. Xavier Prochaska ◽  
Marc Rafelski ◽  
Chris L. Carilli ◽  
...  

2018 ◽  
Vol 621 ◽  
pp. A20 ◽  
Author(s):  
K. E. Heintz ◽  
C. Ledoux ◽  
J. P. U. Fynbo ◽  
P. Jakobsson ◽  
P. Noterdaeme ◽  
...  

We present a survey for neutral atomic-carbon (C I) along gamma-ray burst (GRB) sightlines, which probes the shielded neutral gas-phase in the interstellar medium (ISM) of GRB host galaxies at high redshift. We compile a sample of 29 medium- to high-resolution GRB optical afterglow spectra spanning a redshift range through most of cosmic time from 1 <  z <  6. We find that seven (≈25%) of the GRBs entering our statistical sample have C I detected in absorption. It is evident that there is a strong excess of cold gas in GRB hosts compared to absorbers in quasar sightlines. We investigate the dust properties of the GRB C I absorbers and find that the amount of neutral carbon is positively correlated with the visual extinction, AV, and the strength of the 2175 Å dust extinction feature, Abump. GRBs with C I detected in absorption are all observed above a certain threshold of logN(H I)/cm−2 + [X/H] > 20.7 and a dust-phase iron column density of logN(Fe)dust/cm−2 > 16.2. In contrast to the SED-derived dust properties, the strength of the C I absorption does not correlate with the depletion-derived dust properties. This indicates that the GRB C I absorbers trace dusty systems where the dust composition is dominated by carbon-rich dust grains. The observed higher metal and dust column densities of the GRB C I absorbers compared to H2- and C I-bearing quasar absorbers is mainly a consequence of how the two absorber populations are selected, but is also required in the presence of intense UV radiation fields in actively star-forming galaxies.


2017 ◽  
Vol 471 (3) ◽  
pp. 3428-3442 ◽  
Author(s):  
Sandhya M. Rao ◽  
David A. Turnshek ◽  
Gendith M. Sardane ◽  
Eric M. Monier

2001 ◽  
Vol 326 (4) ◽  
pp. 1475-1488 ◽  
Author(s):  
Ariyeh H. Maller ◽  
Jason X. Prochaska ◽  
Rachel S. Somerville ◽  
Joel R. Primack

2019 ◽  
Vol 15 (S359) ◽  
pp. 413-414
Author(s):  
María P. Agüero ◽  
Rubén Díaz ◽  
Mischa Schirmer

AbstractThis work is focused on the characterization of the Seyfert-2 galaxies hosting very large, ultra-luminous narrow-line regions (NLRs) at redshifts z = 0.2−0.34. With a space density of 4.4 Gcp−3 at z ∼ 0.3, these “Low Redshift Lyman-α Blob” (LAB) host galaxies are amongst the rarest objects in the universe, and represent an exceptional and short-lived phenomenon in the life cycle of active galactic nuclei (AGNs). We present the study of GMOS spectra for 13 LAB galaxies covering the rest frame spectral range 3700–6700 Å. Predominantly, the [OIII]λ5007 emission line radial distribution is as widespread as that of the continuum one. The emission line profiles exhibit FWHM between 300–700 Km s−1. In 7 of 13 cases a broad kinematical component is detected with FWHM within the range 600–1100 Km s−1. The exceptionally high [OIII]λ5007 luminosity is responsible for very high equivalent width reaching 1500 Å at the nucleus.


2012 ◽  
Vol 8 (S292) ◽  
pp. 188-188
Author(s):  
J. R. Allison ◽  
E. M. Sadler ◽  
S. J. Curran ◽  
S. N. Reeves

AbstractRecent targeted studies of associated H i absorption in radio galaxies are starting to map out the location, and potential cosmological evolution, of the cold gas in the host galaxies of Active Galactic Nuclei (AGN). The observed 21 cm absorption profiles often show two distinct spectral-line components: narrow, deep lines arising from cold gas in the extended disc of the galaxy, and broad, shallow lines from cold gas close to the AGN (e.g. Morganti et al. 2011). Here, we present results from a targeted search for associated H i absorption in the youngest and most recently-triggered radio AGN in the local universe (Allison et al. 2012b). So far, by using the recently commissioned Australia Telescope Compact Array Broadband Backend (CABB; Wilson et al. 2011), we have detected two new absorbers and one previously-known system. While two of these show both a broad, shallow component and a narrow, deep component (see Fig. 1), one of the new detections has only a single broad, shallow component. Interestingly, the host galaxies of the first two detections are classified as gas-rich spirals, while the latter is an early-type galaxy. These detections were obtained using a spectral-line finding method, based on Bayesian inference, developed for future large-scale absorption surveys (Allison et al. 2012a).


2018 ◽  
Vol 617 ◽  
pp. A62 ◽  
Author(s):  
Anna Feltre ◽  
Roland Bacon ◽  
Laurence Tresse ◽  
Hayley Finley ◽  
David Carton ◽  
...  

The physical origin of the near-ultraviolet Mg II emission remains an underexplored domain, unlike more typical emission lines that are detected in the spectra of star-forming galaxies. We explore the nebular and physical properties of a sample of 381 galaxies between 0.70 < z < 2.34 drawn from the MUSE Hubble Ultra Deep Survey. The spectra of these galaxies show a wide variety of profiles of the Mg II λλ2796, 2803 resonant doublet, from absorption to emission. We present a study on the main drivers for the detection of Mg II emission in galaxy spectra. By exploiting photoionization models, we verified that the emission-line ratios observed in galaxies with Mg II in emission are consistent with nebular emission from HII regions. From a simultaneous analysis of MUSE spectra and ancillary Hubble Space Telescope information through spectral energy distribution fitting, we find that galaxies with Mg II in emission have lower stellar masses, smaller sizes, bluer spectral slopes, and lower optical depth than those with absorption. This leads us to suggest that Mg II emission is a potential tracer of physical conditions that are not merely related to those of the ionized gas. We show that these differences in Mg II emission and absorption can be explained in terms of a higher dust and neutral gas content in the interstellar medium (ISM) of galaxies showing Mg II in absorption, which confirms the extreme sensitivity of Mg II to the presence of the neutral ISM. We conclude with an analogy between the Mg II doublet and the Ly α line that lies in their resonant nature. Further investigations with current and future facilities, including the James Webb Space Telescope, are promising because the detection of Mg II emission and its potential connection with Lyα could provide new insights into the ISM content in the early Universe.


2006 ◽  
pp. 330-333
Author(s):  
Andrew Bunker ◽  
Annette Ferguson ◽  
Rachel Johnson ◽  
Richard McMahon ◽  
Ian Parry ◽  
...  

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