The dark nature of GRB 130528A and its host galaxy

Abstract

We study the dark nature of GRB 130528A through multi-wavelength observations and conclude that the main reason for the optical darkness is local extinction inside of the host galaxy. Automatic observations were performed at BOOTES-4/MET robotic telescope. We also triggered target of opportunity (ToO) observation at the OSN, IRAM PdBI and the GTC+OSIRIS. The host galaxy photometric observations in optical to near-infrared (nIR) wavelengths were achieved through large ground-based aperture telescopes, such as the 10.4m GTC, the 4.2m WHT, 6m BTA, and the 2m LT. Based on these observations, spectral energy distributions (SED) for the host galaxy and afterglow were constructed. Thanks to mm observations at PdBI, we confirm the presence of a mm source within the XRT error circle that faded over the course of our observations and identify the host galaxy. However, we do not find any credible optical source within early observations with BOOTES-4/MET and 1.5m OSN telescopes. Spectroscopic observation of this galaxy by GTC showed a single faint emission line that likely corresponds to [OII] 3727\{AA} at a redshift of 1.250+/-0.001 implying a SFR(M_sun/yr) > 6.18 M_sun/yr without correcting for dust extinction. The probable extinction was revealed through analysis of the afterglow SED, resulting in a value of AV >= ~ 0.9 at the rest frame, this is comparable to extinction levels found among other dark GRBs. The SED of the host galaxy is explained well (chi2/d.o.f.=0.564) by a luminous (MB=-21.16), low-extinction (AV =0, rest frame), and aged (2.6 Gyr) stellar population. We can explain this apparent contradiction in global and line-of-sight extinction if the GRB birth place happened to lie in a local dense environment. In light of having relatively small specific SFR (SSFR) ~ 5.3 M_sun/yr (L/L_star)-1, this also could explain the age of the old stellar population of host galaxy.

arXiv comment6 pages, 4 figures

References in corpus (27)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Star Formation in Galaxies Along the Hubble Sequence
• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• Spectra and Light Curves of Gamma-Ray Burst Afterglows
• Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of GRBs
• Jets in GRBs
• Empirical Color Transformations Between SDSS Photometry and Other Photometric Systems
• Physical parameters of GRB 970508 and GRB 971214 from their afterglow synchrotron emission
• UV star-formation rates of GRB host galaxies
• The nature of "dark" gamma-ray bursts
• Swift Identification of Dark Gamma-Ray Bursts
• A Population of Massive, Luminous Galaxies Hosting Heavily Dust-Obscured Gamma-Ray Bursts: Implications for the Use of GRBs as Tracers of Cosmic Star Formation
• The Host Galaxies of Swift Dark Gamma-Ray Bursts: Observational Constraints on Highly Obscured and Very High-Redshift GRBs
• The SEDs and Host Galaxies of the dustiest GRB afterglows
• Detection of the optical afterglow of GRB 000630: Implications for dark bursts
• Dust and Metal Column Densities in Gamma-Ray Burst Host Galaxies
• A Search for Optical Afterglow from GRB970828
• The X-ray absorbing column density of a complete sample of bright Swift Gamma-Ray Bursts
• New light on gamma-ray burst host galaxies with Herschel
• How Special Are Dark Gamma-Ray Bursts: A Diagnostic Tool
• A comparative study of the X-ray afterglow properties of optically bright and dark GRBs
• Optical Classification of Gamma-Ray Bursts in the Swift Era
• A deep search for the host galaxies of GRBs with no detected optical afterglow
• A multi-colour study of the dark GRB 000210 host galaxy and its environment
• The Dark Bursts population in a complete sample of bright Swift Long Gamma-Ray Bursts
• The dark nature of GRB 051022 and its host galaxy
• The blue host galaxy of the red GRB 000418

Cited by in corpus (9)

• Measurements of the Temperature and E-Mode Polarization of the CMB from 500 Square Degrees of SPTpol Data
• A Comparative Study of Long and Short GRBs. I. Overlapping Properties
• A comprehensive statistical study on gamma-ray bursts
• Investigating a population of infrared-bright gamma-ray burst host galaxies
• A Large Catalog of Homogeneous Ultra-Violet/Optical GRB Afterglows: Temporal and Spectral Evolution
• Swift/UVOT: 18 Years of Long GRB Discoveries and Advances
• Possible correlations between gamma-ray burst and its host galaxy offset
• The Case for a High-Redshift Origin of GRB100205A
• A Radio-selected Population of Dark, Long Gamma-ray Bursts: Comparison to the Long Gamma-ray Burst Population and Implications for Host Dust Distributions