<i>XMM-Newton</i> observations of the BL Lac MS 0205.7+3509:
   A dense, low-metallicity absorber

Watson, Derrick G.; McBreen, B.; Hanlon, L.; Reeves, J. N.; Smith, N.; Perlman, Eric S.; Stocke, John T.; Rector, T. A.

doi:10.1051/0004-6361:20034524

Cited by 5 publications

(4 citation statements)

References 21 publications

(27 reference statements)

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“…This suggestion is supported by the observations of Falomo et al (1997) and Watson et al (2004), who find a likely counterpart to an Mg  absorption system in a BL Lac object at only D = 11 kpc. In addition, Ellison et al (2004) analysed 27 intervening absorption systems in the spectra of a triply imaged QSO.…”

Section: The Intervening Absorption Galaxysupporting

confidence: 75%

“…A large fraction of possible OAs appears to have a faint absorber at small D. These results imply that some previous QSO absorption-selected galaxy counterpart identifications may be incorrect, with the real absorber being a nearby faint galaxy. This suggestion is supported by the observations of Falomo et al (1997) and Watson et al (2004), who find a likely counterpart to an Mg  absorption system in a BL Lac object at only D = 11 kpc. In addition, Ellison et al (2004) analysed 27 intervening absorption systems in the spectra of a triply imaged QSO.…”

Section: The Intervening Absorption Galaxysupporting

confidence: 75%

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The line-of-sight towards GRB 030429 at z $\mathsf{=2.66}$: Probing the matter at stellar, galactic and intergalactic scales

Jakobsson

Hjorth²,

Fynbo

et al. 2004

A&A

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108

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Abstract. We report the discovery of the optical afterglow (OA) of the long-duration gamma-ray burst GRB 030429, and present a comprehensive optical/near-infrared dataset used to probe the matter at different distance scales, i.e. in the burst environment, in the host galaxy and in an intervening absorber. A break in the afterglow light curve is seen approximately 1 day from the onset of the burst. The light curve displays a significant deviation from a simple broken power-law with a bright 1.5 mag bump with a duration of 2-3 days. The optical/near-infrared spectral energy distribution is best fit with a power-law with index β = −0.36 ± 0.12 reddened by an SMC-like extinction law with (a modest) A V = 0.34 ± 0.04. In addition, we present deep spectroscopic observations obtained with the Very Large Telescope. The redshift measured via metal absorption lines in the OA is z = 2.658 ± 0.004. Based on the damped Lyα absorption line in the OA spectrum we measure the H  column density to be log N(H i) = 21.6 ± 0.2. This confirms the trend that GRBs tend to be located behind very large H  column densities.The resulting dust-to-gas ratio is consistent with that found in the SMC, indicating a low metallicity and/or a low dust-to-metal ratio in the burst environment. We find that a neighbouring galaxy, at a separation of only 1. 2, has z = 0.841 ± 0.001, ruling it out as the host of GRB 030429. The small impact parameter of this nearby galaxy, which is responsible for Mg  absorption in the OA spectrum, is in contrast to previous identifications of most QSO absorption-selected galaxy counterparts. Finally, we demonstrate that the OA was not affected by strong gravitational lensing via the nearby galaxy.

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Section: The Intervening Absorption Galaxysupporting

confidence: 75%

Section: The Intervening Absorption Galaxysupporting

confidence: 75%

The line-of-sight towards GRB 030429 at z $\mathsf{=2.66}$: Probing the matter at stellar, galactic and intergalactic scales

Jakobsson

Hjorth²,

Fynbo

et al. 2004

A&A

Self Cite

108

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“…However, the absence of an intrinsic O i edge is inconsistent with absorption from the neutral interstellar medium (ISM) of the host galaxy. A similar break is seen in XMM-Newton spectra of the BL Lac object MS 0205.7+3509, and is attributed to a lowmetallicity intervening absorber (Watson et al 2004). For a high excess H i column density, we would expect to see damped Lyα absorption in the UV spectrum of 3C 120.…”

Section: Soft X-ray Spectrumsupporting

confidence: 65%

Multiwavelength Observations of Radio Galaxy 3C 120 withXMM‐Newton

Ogle

Davis

Antonucci

et al. 2005

ApJ

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We present XMM-Newton observations of the radio galaxy 3C 120, which we use to study the nature and geometry of the X-ray and UV-emitting regions. Contemporaneous radio, mm-wave, and optical data provide additional constraints on the spectral energy distribution and physical state of the active galactic nucleus. The hard X-ray spectrum contains a marginally resolved Fe i Kα emission line with FWHM= 9, 000 ± 3, 000 km s −1 and an equivalent width of 57 ± 7 eV. The line arises via fluorescence in a broad-line region with covering fraction of 0.4. There is no evidence of relativistically broad Fe Kα, contrary to some previous reports. The normal equivalent widths of the X-ray and optical emission lines exclude a strongly beamed synchrotron component to the hard X-ray and optical continua. There is an excess of 0.3-2 keV soft Xray continuum over an extrapolation of the hard X-ray power-law, which may arise in a disk corona. Analysis of an archival Chandra image shows that extended emission from the jet and other sources contributes < 3% of the total X-ray flux. A break in the X-ray spectrum below 0.6 keV indicates an excess neutral hydrogen column density of N H = 1.57 ± 0.03 × 10 21 cm −2 . However, the neutral absorber must have an oxygen abundance of < 1/50 of the solar value to explain the absence of an intrinsic or intervening O i edge. There is no ionized absorption in the soft X-ray spectrum, but there is a weak, narrow O viii Lyα emission line. We do not detect previously claimed O viii absorption from the intervening intergalactic medium. Radio observations at 37 GHz show a fast, high frequency flare starting 7 days after the XMM-Newton observation. However, this has no obvious effect on the X-ray spectrum. The X-ray spectrum, including the soft excess, became harder as the X-ray flux decreased, with an estimated pivot energy of 40 keV. The UV and soft X-ray fluxes are strongly correlated over the 120 ks duration of the XMM-Newton observation. This is qualitatively consistent with Comptonization of UV photons by a hot corona.

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“…Furthermore, the apparent 'absorption' observed in low redshift blazars is peculiar in that no atomic absorption edges or lines are ever observed (e.g. Watson et al 2004;Blustin et al 2004), further strengthening the conclusion that the observed downturns are in fact due to intrinsic curvature. Therefore, finding evidence of such curvature in some higher redshift radio-loud AGN should not be a surprise.…”

Section: The Warm-hot Intergalactic Mediummentioning

confidence: 69%

DUST EXTINCTION BIAS IN THE COLUMN DENSITY DISTRIBUTION OF GAMMA-RAY BURSTS: HIGH COLUMN DENSITY, LOW-REDSHIFT GRBs ARE MORE HEAVILY OBSCURED

Watson

Jakobsson

2012

ApJ

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The afterglows of gamma-ray bursts (GRBs) have more soft X-ray absorption than expected from the foreground gas column in the Galaxy. While the redshift of the absorption can in general not be constrained from current X-ray observations, it has been assumed that the absorption is due to metals in the host galaxy of the GRB. The large sample of X-ray afterglows and redshifts now available allows the construction of statistically meaningful distributions of the metal column densities. We construct such a sample and show, as found in previous studies, that the typical absorbing column density (N HX ) increases substantially with redshift, with few high column density objects found at low to moderate redshifts. We show, however, that when highly extinguished bursts are included in the sample, using redshifts from their host galaxies, high column density sources are also found at low to moderate redshift. We infer from individual objects in the sample and from observations of blazars, that the increase in column density with redshift is unlikely to be related to metals in the intergalactic medium or intervening absorbers. Instead we show that the origin of the apparent increase with redshift is primarily due to dust extinction bias: GRBs with high X-ray absorption column densities found at z 4 typically have very high dust extinction column densities, while those found at the highest redshifts do not. It is unclear how such a strongly evolving N HX /A V ratio would arise, and based on current data, remains a puzzle.

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XMM-Newton observations of the BL Lac MS 0205.7+3509: A dense, low-metallicity absorber

Cited by 5 publications

References 21 publications

The line-of-sight towards GRB 030429 at z $\mathsf{=2.66}$: Probing the matter at stellar, galactic and intergalactic scales

The line-of-sight towards GRB 030429 at z $\mathsf{=2.66}$: Probing the matter at stellar, galactic and intergalactic scales

Multiwavelength Observations of Radio Galaxy 3C 120 withXMM‐Newton

DUST EXTINCTION BIAS IN THE COLUMN DENSITY DISTRIBUTION OF GAMMA-RAY BURSTS: HIGH COLUMN DENSITY, LOW-REDSHIFT GRBs ARE MORE HEAVILY OBSCURED

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