Steep extinction towards GRB 140506A reconciled from host galaxy observations: Evidence that steep reddening laws are local

	Steep extinction towards GRB 140506A reconciled from host galaxy observations: Evidence that steep reddening laws are local
	Heintz, K. E.1,2; Fynbo, J. P. U.2; Jakobsson, P.1; Kruehler, T.3; Christensen, L.2; Watson, D.2; Ledoux, C.4; Noterdaeme, P.5; Perley, D. A.2,6; Rhodin, H.2
刊名	ASTRONOMY & ASTROPHYSICS
	2017-05-01
卷号	601
关键词	gamma-ray burst: general gamma-ray burst: individual: GRB 140506A dust, extinction galaxies: individual: GRB 140506A host
英文摘要	We present the spectroscopic and photometric late-time follow-up of the host galaxy of the long-duration Swift gamma-ray burst GRB 140506A at z = 0.889. The optical and near-infrared afterglow of this GRB had a peculiar spectral energy distribution (SED) with a strong flux-drop at 8000 angstrom (4000 angstrom rest-frame) suggesting an unusually steep extinction curve. By analyzing the contribution and physical properties of the host galaxy, we here aim at providing additional information on the properties and origin of this steep, non-standard extinction. We find that the strong flux-drop in the GRB afterglow spectrum at < 8000 angstrom and rise at < 4000 angstrom is well explained by the combination of a steep extinction curve along the GRB line of sight and contamination by the host galaxy light so that the scenario with an extreme 2175 angstrom extinction bump can be excluded. We localise the GRB to be at a projected distance of approximately 4 kpc from the centre of the host galaxy. Based on emission-line diagnostics of the four detected nebular lines, H alpha, H beta, [O II] and [O III], we find the host to be a modestly star forming (SFR = 1.34 +/- 0.04 M circle dot yr(-1)) and relatively metal poor (Z = 0.35(-0.11)(+0.15)Z circle dot) galaxy with a large dust content, characterized by a measured visual attenuation of A_V = 1.74 +/- 0.41 mag, thus unexceptional in all its physical properties. We model the extinction curve of the host-corrected afterglow and show that the standard dust properties causing the reddening seen in the Local Group are inadequate in describing the steep drop. We conclude that the steep extinction curve seen in the afterglow towards the GRB is of exotic origin, is sightline-dependent only and thus solely a consequence of the circumburst environment.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	GAMMA-RAY BURSTS ; OXYGEN ABUNDANCE DETERMINATION ; STAR-FORMING GALAXIES ; IA SUPERNOVAE ; AFTERGLOW SPECTROSCOPY ; HII-REGIONS ; COLUMN DENSITIES ; DUST CONTENT ; MILKY-WAY ; X-SHOOTER
收录类别	SCI
语种	英语
WOS记录号	WOS:000402313500083
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/8803]
专题	国家天文台_光学天文研究部
作者单位	1.Univ Iceland, Sci Inst, Ctr Astrophys & Cosmol, Dunhagi 5, IS-107 Reykjavik, Iceland 2.Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, Juliane Maries Vej 30, DK-2100 Copenhagen O, Denmark 3.Max Planck Inst Extraterr Phys, Giessenbachstr, D-85748 Garching, Germany 4.European Southern Observ, Alonso de Cordova 3107,Casilla 19001, Santiago 19, Chile 5.UPMC, CNRS, UMR 7095, Inst Astrophys Paris, 98 Bis Bd Arago, F-75014 Paris, France 6.Liverpool John Moores Univ, Astrophys Res Inst, IC2,Liverpool Sci Pk,146 Brownlow Hill, Liverpool L3 5RF, Merseyside, England 7.Weizmann Inst Sci, Dept Particle Phys & Astrophys, IL-7610001 Rehovot, Israel 8.Univ Leicester, Dept Phys & Astron, Univ Rd, Leicester LE1 7RH, Leics, England 9.European Southern Observ, Karl Schwarzschildstr 2, D-85748 Garching, Germany 10.Univ Paris Diderot, APC, CNRS IN2P3, CEA Irfu,Observ Paris,Sorbonne Paris Cite, Paris, France
推荐引用方式 GB/T 7714	Heintz, K. E.,Fynbo, J. P. U.,Jakobsson, P.,et al. Steep extinction towards GRB 140506A reconciled from host galaxy observations: Evidence that steep reddening laws are local[J]. ASTRONOMY & ASTROPHYSICS,2017,601.
APA	Heintz, K. E..,Fynbo, J. P. U..,Jakobsson, P..,Kruehler, T..,Christensen, L..,...&Milvang-Jensen, B..(2017).Steep extinction towards GRB 140506A reconciled from host galaxy observations: Evidence that steep reddening laws are local.ASTRONOMY & ASTROPHYSICS,601.
MLA	Heintz, K. E.,et al."Steep extinction towards GRB 140506A reconciled from host galaxy observations: Evidence that steep reddening laws are local".ASTRONOMY & ASTROPHYSICS 601(2017).