Galaxy gas as obscurer – I. GRBs x-ray galaxies and find an $N_{{\rm H}}^{3}\propto M_{\star }$ relation

Buchner, Johannes; Schulze, S.; Bauer, F. E.

doi:10.1093/mnras/stw2423

Cited by 48 publications

(40 citation statements)

References 92 publications

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“…Our selection of red quasars is broadly consistent with E(B − V) > 0.04 at z > 0.8 for a blue quasar SED. This corresponds to an equivalent hydrogen column density of N H > 2.8 × 10 20 cm −2 assuming an SMC-like dust-to-gas (E(B − V)/N H ) ratio, comparable to that found towards the HII-regions in normal galaxies (Buchner et al 2017); we note that LaMassa et al…”

Section: Dust Extinction In Red Quasarssupporting

confidence: 82%

Fundamental differences in the radio properties of red and blue quasars: evolution strongly favoured over orientation

Klindt

Alexander

Rosario

et al. 2019

Monthly Notices of the Royal Astronomical Society

197

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A minority of the optically selected quasar population are red at optical wavelengths due to the presence of dust along the line-of-sight. A key focus of many red quasar studies is to understand their relationship with the overall quasar population: are they blue quasars observed at a (slight) inclination angle or do they represent a transitional phase in the evolution of quasars? Identifying fundamental differences between red and blue quasars is key to discriminate between these two paradigms. To robustly explore this, we have uniformly selected quasars from the Sloan Digital Sky Survey with midinfrared counterparts, carefully controlling for luminosity and redshift effects. We take a novel approach to distinguish between colour-selected quasars in the redshift range of 0.2 < z < 2.4 by constructing redshift-sensitive g * −i * colour cuts. From cross-matching this sample to the Faint Images of the Radio Sky at Twenty-centimeters (FIRST) survey, we have found a factor ≈ 3 larger fraction of radio-detected red quasars with respect to that of blue quasars. Through a visual inspection of the FIRST images and an assessment of the radio luminosities (rest-frame L 1.4 GHz and L 1.4 GHz /L 6µm ) we find that the radio-detection excess for red quasars is primarily due to compact and radio-faint systems (around the radio quiet-radio loud threshold). We show that our results rule out orientation as the origin for the differences between red and blue quasars and argue that they provide broad agreement with an evolutionary model.

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Section: Dust Extinction In Red Quasarssupporting

confidence: 82%

Fundamental differences in the radio properties of red and blue quasars: evolution strongly favoured over orientation

Klindt

Alexander

Rosario

et al. 2019

Monthly Notices of the Royal Astronomical Society

197

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“…Instead, a correlation between N H,X and host stellar mass is suggested. Assuming that the different N H,X -fitting methodologies yield comparable results, GRB 111117A has a higher N H,X compared to the relation suggested by Buchner et al (2017) by more than the intrinsic scatter, although some lGRB hosts populate a similar region in the N H,X -M relation. The large offset of GRB 111117A relative to the host center derived in Margutti et al (2012) and Sakamoto et al (2013) is difficult to reconcile with galaxy-scale gas being the source of the X-ray absorption.…”

Section: Rest-frame N Hxmentioning

confidence: 87%

“…The redshift evolution of N H,X in the hosts of lGRBs is not reproduced by Buchner et al (2017), who use a different N H,X inference methodology. Instead, a correlation between N H,X and host stellar mass is suggested.…”

Section: Rest-frame N Hxmentioning

confidence: 95%

The host galaxy of the short GRB 111117A at z = 2.211

Selsing

Krühler

Malesani

et al. 2018

A&A

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It is notoriously difficult to localize short γ-ray bursts (sGRBs) and their hosts to measure their redshifts. These measurements, however, are critical for constraining the nature of sGRB progenitors, their redshift distribution, and the r-process element enrichment history of the universe. Here we present spectroscopy of the host galaxy of GRB 111117A and measure its redshift to be z = 2.211. This makes GRB 111117A the most distant high-confidence short duration GRB detected to date. Our spectroscopic redshift supersedes a lower, previously estimated photometric redshift value for this burst. We use the spectroscopic redshift, as well as new imaging data to constrain the nature of the host galaxy and the physical parameters of the GRB. The rest-frame X-ray derived hydrogen column density, for example, is the highest compared to a complete sample of sGRBs and seems to follow the evolution with redshift as traced by the hosts of long GRBs. From the detection of Lyα emission in the spectrum, we are able to constrain the escape fraction of Lyα in the host. The host lies in the brighter end of the expected sGRB host brightness distribution at z = 2.211, and is actively forming stars. Using the observed sGRB host luminosity distribution, we find that between 43% and 71% of all Swift-detected sGRBs have hosts that are too faint at z ~ 2 to allow for a secure redshift determination. This implies that the measured sGRB redshift distribution could be incomplete at high redshift. The high z of GRB 111117A is evidence against a lognormal delay-time model for sGRBs through the predicted redshift distribution of sGRBs, which is very sensitive to high-z sGRBs. From the age of the universe at the time of GRB explosion, an initial neutron star (NS) separation of a0 < 3.1 R⊙ is required in the case where the progenitor system is a circular pair of inspiralling NSs. This constraint excludes some of the longest sGRB formation channels for this burst.

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“…Further, obscuration of the AGN or dilu-tion of stellar processes can be produced in the host galaxy, independent of the small-scale orientation of the central engine (e.g. Chen et al, 2015;Buchner et al, 2017). A more complete "weak" unified model is one in which all these components (L/L Edd , torus covering factor, jet strength, and host galaxy properties as well as orientation) come together to produce the observed signatures of an AGN.…”

Section: Unification and The Importance Of Timescalesmentioning

confidence: 99%

Active galactic nuclei: what’s in a name?

Padovani

Alexander

Assef

et al. 2017

Astron Astrophys Rev

618

429

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Active Galactic Nuclei (AGN) are energetic astrophysical sources powered by accretion onto supermassive black holes in galaxies, and present unique observational signatures that cover the full electromagnetic spectrum over more than twenty orders of magnitude in frequency. The rich phenomenology of AGN has resulted in a large number of different "flavours" in the literature that now comprise a complex and confusing AGN "zoo". It is increasingly clear that these classifications are only partially related to intrin- sic differences between AGN, and primarily reflect variations in a relatively small number of astrophysical parameters as well the method by which each class of AGN is selected. Taken together, observations in different electromagnetic bands as well as variations over time provide complementary windows on the physics of different sub-structures in the AGN. In this review, we present an overview of AGN multi-wavelength properties with the aim of painting their "big picture" through observations in each electromagnetic band from radio to γ-rays as well as AGN variability. We address what we can learn from each observational method, the impact of selection effects, the physics behind the emission at each wavelength, and the potential for future studies. To conclude we use these observations to piece together the basic architecture of AGN, discuss our current understanding of unification models, and highlight some open questions that present opportunities for future observational and theoretical progress.

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Galaxy gas as obscurer – I. GRBs x-ray galaxies and find an $N_{{\rm H}}^{3}\propto M_{\star }$ relation

Cited by 48 publications

References 92 publications

Fundamental differences in the radio properties of red and blue quasars: evolution strongly favoured over orientation

Fundamental differences in the radio properties of red and blue quasars: evolution strongly favoured over orientation

The host galaxy of the short GRB 111117A at z = 2.211

Active galactic nuclei: what’s in a name?

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