Michałowski 2013 GRB 980425 的宿主星系

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在800pc远的地方发现了WR星群的信号。

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Title:		Spatially-resolved dust properties of the GRB 980425 host galaxy
Authors:		Michałowski, Michał J.; Hunt, L. K.; Palazzi, E.; Savaglio, S.; Gentile, G.; Rasmussen, J.; Baes, M.; Basa, S.; Bianchi, S.; Berta, S.; Burlon, D.; Castro Ceron, J. M.; Covino, S.; Cuby, J.-G.; D'Elia, V.; Ferrero, P.; Gotz, D.; Hjorth, J.; Koprowski, M. P.; Le Borgne, D.; Le Floc'h, E.; Malesani, D.; Murphy, T.; Pian, E.; Piranomonte, S.; Rossi, A.; Sollerman, J.; Tanvir, N. R.; de Ugarte Postigo, A.; Watson, D.; van der Werf, P.; Vergani, S. D.; Xu, D.
Publication:		eprint arXiv:1311.6466
Publication Date:		11/2013
Origin:		ARXIV
Keywords:		Astrophysics - Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Comment:		Accepted by A&A. 14 pages, 7 figures, 2 tables
Bibliographic Code:		2013arXiv1311.6466M

Abstract

Gamma-ray bursts (GRBs) have been proposed as a tool to study star formation in the Universe, so it is crucial to investigate whether their host galaxies and immediate environments are in any way special compared with other star-forming galaxies. Here we present spatially resolved maps of dust emission of the host galaxy of the closest known GRB 980425 at z=0.0085 using our new high-resolution observations from Herschel, APEX, ALMA and ATCA. We modeled the spectral energy distributions of the host and of the star-forming region displaying the Wolf-Rayet signatures in the spectrum (WR region), located 800 pc away from the GRB position. The host is characterised by low dust content and high fraction of UV-visible star-formation, similar to other dwarf galaxies. Such galaxies are abundant in the local universe, so it is not surprising to find a GRB in one of them, assuming the correspondence between the GRB rate and star-formation. The WR region contributes substantially to the host emission at the far-infrared, millimeter and radio wavelengths and we propose this to be a consequence of its high gas density. If dense environments are also found close to the positions of other GRBs, then the ISM density should also be considered as an important factor influencing whether a given stellar population can produce a GRB, in a similar way as metallicity.

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Clocchiatti 2011 SN 1998bw/GRB 980425的光变曲线

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Title:		The Ultimate Light Curve of SN 1998bw/GRB 980425
Authors:		Clocchiatti, Alejandro; Suntzeff, Nicholas B.; Covarrubias, Ricardo; Candia, Pablo
Affiliation:		AA(Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile aclocchi@astro.puc.cl), AB(Department of Physics and Astronomy, Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA ; Staff astronomers, Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy, under contract with the National Science Foundation. nsuntzeff@tamu.edu), AC(Australian Astronomical Observatory, P.O. Box 296, Epping, NSW 1710, Australia ; Staff astronomers, Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy, under contract with the National Science Foundation. ricardo@aao.gov.au), AD(Gemini Observatory, Casilla 603, La Serena, Chile ; Staff astronomers, Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy, under contract with the National Science Foundation. pcandia@gemini.edu)
Publication:		The Astronomical Journal, Volume 141, Issue 5, article id. 163 (2011). (AJ Homepage)
Publication Date:		05/2011
Origin:		IOP
AJ Keywords:		gamma-ray burst: general, supernovae: general, supernovae: individual: SN 1998bw
DOI:		10.1088/0004-6256/141/5/163
Bibliographic Code:		2011AJ....141..163C

Abstract

We present multicolor light curves of SN 1998bw which appeared in ESO184-G82 in close temporal and spatial association with GRB 980425. The light curves are based on observations conducted at Cerro Tololo Inter-American Observatory (CTIO) and data from the literature. The CTIO photometry reaches ~86 days after the gamma-ray burst (GRB) in U and ~160 days after the GRB in BV(RI) _C . The observations in U extend the previously known coverage by about 30 days and determine the slope of the early exponential tail. We calibrate a large set of local standards in common with those of previous studies and use them to transform published observations of the supernova (SN) to our realization of the standard photometric system. We show that the photometry from different sources merges smoothly and we provide a unified set of 300 observations of the SN in five bands. Using the extensive set of spectra in the public domain, we compute extinction and K-corrections and build quasi-bolometric unreddened rest-frame light curves. We provide low-degree piecewise spline fits to these light curves with daily sampling. They reach ~86 rest-frame days after the GRB with U-band coverage and ~498 rest-frame days after the GRB without U.

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Bloom 1998 GRB 980425的瞬时光变曲线

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找了好久的这个暴的光变曲线, 居然藏在一个不以980425为标题的文章里.

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Title:		Expected Characteristics of the Subclass of Supernova Gamma-Ray Bursts
Authors:		Bloom, J. S.; Kulkarni, S. R.; Harrison, F.; Prince, T.; Phinney, E. S.; Frail, D. A.
Publication:		The Astrophysical Journal, Volume 506, Issue 2, pp. L105-L108. (ApJ Homepage)
Publication Date:		10/1998
Origin:		APJ
ApJ Keywords:		GAMMA RAYS: BURSTS, STARS: SUPERNOVAE: GENERAL, STARS: SUPERNOVAE: INDIVIDUAL: ALPHANUMERIC: SN 1998BW
Abstract Copyright:		(c) 1998: The American Astronomical Society
DOI:		10.1086/311655
Bibliographic Code:		1998ApJ...506L.105B

Abstract

The spatial and temporal coincidence of gamma-ray burst (GRB) 980425 and supernova (SN) 1998bw has prompted speculation that there exists a subclass of GRBs produced by SNe (``S-GRBs''). A physical model motivated by radio observations lead us to propose the following characteristics of S-GRBs: (1) prompt radio emission and an implied high brightness temperature close to the inverse Compton limit, (2) high expansion velocity (>~50,000 km s^-1) of the optical photosphere as derived from lines widths and energy release larger than usual, (3) no long-lived X-ray afterglow, and (4) a single-pulse GRB profile. Radio studies of previous SNe show that only (but not all) Type Ib and Ic SNe potentially satisfy the first condition. We investigate the proposed associations of GRBs and SNe within the context of these proposed criteria and suggest that ~1% of GRBs detected by BATSE may be members of this subclass.

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Michałowski 2008 GRB 980425的宿主星系的谱

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Title:		The properties of the host galaxy and the immediate environment of GRB 980425 / SN 1998bw from the multi-wavelength spectral energy distribution
Authors:		Michałowski, Michał J.; Hjorth, Jens; Malesani, Daniele; Michałowski, Tadeusz; María Castro Cerón, José; Reinfrank, Robert F.; Garrett, Michael A.; Fynbo, Johan P. U.; Watson, Darach J.; Jørgensen, Uffe G.
Publication:		eprint arXiv:0809.0508
Publication Date:		09/2008
Origin:		ARXIV
Keywords:		Astrophysics
Comment:		9 pages, 3 figures, submitted to ApJ, comments welcome; for SED templates, see http://archive.dark-cosmology.dk/
Bibliographic Code:		2008arXiv0809.0508M

Abstract

We present an analysis of the spectral energy distribution (SED) of the galaxy ESO 184-G82, the host of the closest known long gamma-ray burst (GRB) 980425 and its associated supernova SN 1998bw. We use our observations obtained at the Australia Telescope Compact Array (the third >3 sigma radio detection of a GRB host) as well as archival infrared (IR) and ultraviolet (UV) observations to estimate its star formation state. We find that ESO 184-G82 has a UV star formation rate (SFR) and stellar mass consistent with the population of cosmological GRB hosts and of local dwarf galaxies. It has however a higher specific SFR (per unit stellar mass) and lower molecular gas-to-dust ratio than luminous spiral galaxies. The mass of ESO 184-G82 is dominated by an older stellar population in contrast to the majority of GRB hosts. The Wolf-Rayet region ~800 pc from the supernova site experienced a starburst episode during which the majority of its stellar population was built up. Unlike that of the entire galaxy, its SED is similar to those of cosmological submillimeter/radio-bright GRB hosts with hot dust content. These findings add to the picture that in general, the environments of GRBs on 1-3 kpc scales are associated with high specific SFR and hot dust.

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Christensen 2008 GRB 980425/SN 1998bw的宿主星系

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Title:		IFU observations of the GRB 980425/SN 1998bw host galaxy: emission line ratios in GRB regions
Authors:		Christensen, L.; Vreeswijk, P. M.; Sollerman, J.; Thoene, C. C.; Le Floc'h, E.; Wiersema, K.
Publication:		eprint arXiv:0807.3554
Publication Date:		07/2008
Origin:		ARXIV
Keywords:		Astrophysics
Comment:		16 pages, 10 figures. Accepted for publication in A&A
Bibliographic Code:		2008arXiv0807.3554C

Abstract

The collapsar model predicts that the progenitors of Gamma-ray Bursts (GRBs) are metal poor in Fe group elements. The existence of low metallicity stellar populations could manifest itself through special characteristics of the immediate environment of the GRB site in the host galaxy. We analyse the strong emission lines from the sub-luminous host galaxy of GRB 980425, which showed the first connection with a supernova explosion (SN 1998bw). The host has a sufficient size to allow detailed resolved spectroscopy of individual HII regions and to look for regions with special properties close to the the GRB site. Using integral field spectroscopy with VIMOS we cover most of the high surface brightness part of the host including the HII region where the supernova and GRB occurred. The star formation rate, reddening, equivalent width and stellar mass in the GRB region is similar to other HII regions in the host. Extreme values arise in the only region that shows emission lines from Wolf-Rayet stars; a region that lies 800 pc in projection from the GRB site. Strong emission line diagnostics of all HII regions imply oxygen abundances between 0.3 and 0.8 solar with the lowest values arising in the WR and GRB regions. Comparing the measured emission line ratios for a sample of low redshift GRB hosts to theoretical models and to observations of field galaxies, we find that GRBs arise in a range of metallicity environments while the regions are consistently very young. The similar line ratios of GRB hosts compared to the WR region can arise in spatially unresolved galaxies with bright HII regions near the GRB location. (Abridged)

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Zhang 2008 980425和060218光变

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Title:		Broadband lightcurve characteristics of GRBs 980425 and 060218 and comparison with long-lag, wide-pulse GRBs
Authors:		Zhang, Fu-Wen
Publication:		eprint arXiv:0806.1278
Publication Date:		06/2008
Origin:		ARXIV
Keywords:		Astrophysics
Comment:		26 pages, 10 figures, 3 tables, accepted for publication in ApJ
Bibliographic Code:		2008arXiv0806.1278Z

Abstract

It has been recently argued that low-luminosity gamma-ray bursts (LL-GRBs) are likely a unique GRB population. Here, we present systematic analysis of the lightcurve characteristics from X-ray to gamma-ray energy bands for the two prototypical LL-GRBs 980425 and 060218. It is found that both the pulse width ($w$) and the ratio of the rising width to the decaying width ($r/d$) of theses two bursts are energy-dependent over a broad energy band. There exists a significant trend that the pulses tend to be narrower and more symmetry with respect to the higher energy bands for the two events. Both the X-rays and the gamma-rays follow the same $w - E$ and $r/d - E$ relations. These facts may indicate that the X-ray emission tracks the gamma-ray emission and both are likely to be originated from the same physical mechanism. Their light curves show significant spectral lags. We calculate the three types of lags with the pulse peaking time ($t_{peak}$), the pulse centroid time ($t_{cen}$), and the cross-correlation function (CCF). The derived $t_{peak}$ and $t_{cen}$ are a power-law function of energy. The lag calculated by CCF is strongly correlated with that derived from $t_{peak}$. But the lag derived from $t_{cen}$ is less correlated with that derived from $t_{peak}$ and CCF. The energy dependence of the lags is shallower at higher energy bands. These characteristics are well consistent with that observed in typical long-lag, wide-pulse GRBs, suggesting that GRBs 980425 and 060218 may share the similar radiation physics with them.

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mazzali 2001 SN 1998bw Nebular 阶段的谱

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Title:		The Nebular Spectra of the Hypernova SN 1998bw and Evidence for Asymmetry
Authors:		Mazzali, Paolo A.; Nomoto, Ken'ichi; Patat, Ferdinando; Maeda, Keiichi
Publication:		The Astrophysical Journal, Volume 559, Issue 2, pp. 1047-1053. (ApJ Homepage)
Publication Date:		10/2001
Origin:		UCP
ApJ Keywords:		Nuclear Reactions, Nucleosynthesis, Abundances, supernovae: individual (SN 1998bw)
Abstract Copyright:		(c) 2001: The American Astronomical Society
DOI:		10.1086/322420
Bibliographic Code:		2001ApJ...559.1047M

Abstract

The nebular spectra of the energetic Type Ic supernova SN 1998bw (hypernova) are studied. The transition to the nebular phase occurred at an epoch of about 100 days after outburst, which is assumed to coincide with GRB 980425. Early in the nebular epoch the spectra show the characteristics of a typical supernova (SN) Ic spectrum, with strong lines of [O I], Ca II, and Mg I], and lines of [Fe II]. However, the [Fe II] lines are unusually strong for an SN Ic. Also, lines of different elements have different widths, indicating different expansion velocities. In particular, iron appears to expand more rapidly than oxygen. Furthermore, the [O I] nebular lines decline more slowly than the [Fe II] ones, signaling deposition of γ-rays in a slowly moving O-dominated region. These facts suggest that the explosion was aspherical. The absence of [Fe III] nebular lines can be understood if the ejecta are significantly clumped. A schematic picture of what this very unusual stellar explosion may have looked like is presented.

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Tanaka 2007 数值模拟SN 1998bw的不对称爆发

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数值模拟不对称爆发的动力学、核合成和辐射转移。

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Multi-Dimensional Simulations for Early Phase Spectra of Aspherical Hypernovae: SN 1998bw and Off-Axis Hypernovae

Authors: Masaomi Tanaka, Keiichi Maeda, Paolo A. Mazzali, Ken'ichi Nomoto

(Submitted on 23 Aug 2007)

Abstract: Early phase optical spectra of aspherical jet-like supernovae (SNe) are presented. We focus on energetic core-collapse SNe, or hypernovae. Based on hydrodynamic and nucleosynthetic models, radiative transfer in SN atmosphere is solved with a multi-dimensional Monte-Carlo radiative transfer code, SAMURAI. Since the luminosity is boosted in the jet direction, the temperature there is higher than in the equatorial plane by ~ 2,000 K. This causes anisotropic ionization in the ejecta. Emergent spectra are different depending on viewing angle, reflecting both aspherical abundance distribution and anisotropic ionization. Spectra computed with an aspherical explosion model with kinetic energy 20 x 10^{51} ergs are compatible with those of the Type Ic SN 1998bw if ~ 10-20% of the synthesized metals are mixed out to higher velocities. The simulations enable us to predict the properties of off-axis hypernovae. Even if an aspherical hypernova explosion is observed from the side, it should show hypernova-like spectra but with some differences in the line velocity, the width of the Fe absorptions and the strength of the Na I line.

arXiv:0708.3242 [ps, pdf, other]

Maeda 2007 超新星喷流的观测证据

主要内容:
认为超新星的爆发也是喷流的，并拟合了一下980425.

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Supernovae in Three-Dimension: A Link to Gamma-Ray Bursts

Authors: Keiichi Maeda

(Submitted on 7 Aug 2007)

Abstract: Observational consequences of a jet-driven supernova (SN) explosion model are presented. The results are compared in detail with optical observations of SN 1998bw associated with a Gamma-Ray Burst. It is shown that the jet model is able to reproduce virtually all the optical observations available for this SN, although a spherical model fails to explain some of observed features. Because of the viewing angle effect, the required kinetic energy of the SN ejecta is reduced to ~ 2 x 10^{52} erg as compared to that obtained by the previous spherical model (~ 5 x 10^{52} erg), but this is still much larger than that of a canonical SN (~10^{51} erg).

Comments:	6 pages, 3 figures. Invited talk at "Frascati Workshop 2007: Multifrequency Behaviour of High Energy Cosmic Sources", 28 May - 2 June, 2007, Vulcano, Italy. To apper in the Chinese Journal of Astronomy and Astrophysics (ChJAA)
Subjects:	Astrophysics (astro-ph)
Cite as:	arXiv:0708.0970v1 [astro-ph]

Li 2007 SN 1998bw 的射电光变

主要内容:
作者认为是在星风环境下的激波,考虑同步自吸收。而两个峰的解释是第二个峰来自于能量注入。

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The Astrophysical Journal, 526:716-726, 1999 December 1
© 1999. The American Astronomical Society. All rights reserved. Printed in U.S.A.

Radio Supernova SN 1998bw and Its Relation to GRB 980425

Zhi-Yun Li and Roger A. Chevalier
Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903; zl4h@virginia.edu, rac5x@virginia.edu

ABSTRACT

SN 1998bw is an unusual Type Ic supernova that may be associated with the -ray burst GRB 980425. We use a synchrotron self-absorption model for its radio emission to deduce that the synchrotron-emitting gas is expanding into a circumstellar medium of approximately r^-2 density profile at a speed comparable to the speed of light. We assume that the efficiencies of production of relativistic electrons and magnetic field are constant through the evolution. The circumstellar density is consistent with that expected around the massive star core thought to be the progenitor of SN 1998bw. The explosion energy in material moving with velocity greater than 0.5c is 10⁴⁹ - (3 × 10⁵⁰) ergs, with some preference for the high values. The rise in the radio light curves observed at days 2040 is inferred to be the result of a rise in the energy of the blast wave by a factor of 2.5. Interaction with a jump in the ambient density is not consistent with the observed evolution. We infer that the boost in energy is from a shell of matter from the explosion that catches up with the decelerating shock front. Both the high explosion energy and the nature of the energy input to the blast wave are difficult to reconcile with energy input from the shock-accelerated high-velocity ejecta from a supernova. The implication is that there is irregular energy input from a central engine, which is the type of model invoked for normal -ray bursts. The link between SN 1998bw and GRB 980425 is thus strengthened.

Daigne 2007 低光度GRB980425的两种可能解释

主要内容:
分析了低光度的来源的两个原因：或者是偏轴，或者暴本身的高度低。前者要求很强的余辉观测，但没有看到，所以作者倾向于后者。

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arXiv:0707.0931 [ps, pdf, other]

Title: The low-luminosity tail of the GRB distribution: the case of GRB 980425

Authors: F. Daigne (1), R. Mochkovitch (1) ((1) Institut d'Astrophysique de Paris and Universite Pierre et Marie Curie, Paris)

Comments: 10 pages, 7 figures

Journal-ref: A&A 465, 1-8 (2007)

Subjects: Astrophysics (astro-ph)

(abridged) The association of GRB 980425 with SN 1998bw at z=0.0085 implies the existence of a population of GRBs with an isotropic-equivalent luminosity which is about 10^4 times smaller than in the standard cosmological case. We investigate two scenarios to explain a weak GRB : a normal (intrinsically bright) GRB seen off-axis or an intrinsically weak GRB seen on-axis. For each of these two scenarios, we first derive the conditions to produce a GRB 980425-like event and we then discuss the consequences for the event rate. If we exclude the possibility that GRB 980425 is an occurence of an extremely rare event observed by chance during the first eight years of the 'afterglow era', the first scenario implies that (i) the local rate of standard bright GRBs is much higher than what is usually expected; (ii) the typical opening angle is much narrower than what is derived from observations of a break in the afterglow lightcurve. In addition, we show that the afterglow of GRB 980425 in this scenario should have been very bright and easily detected. For these reasons the second scenario appears more realistic. We show that the parameter space of the internal shock model indeed allows GRB 980425-like events, in cases where the outflow is only mildly-relativistic and mildly-energetic. The rate of such weak events in the Universe has to be much higher than the rate of standard bright GRBs to allow the discovery of GRB 980425 during a short period of a few years. However it is still compatible with the observations as the intrinsic weakness of these GRB 980425-like bursts does not allow detection at cosmological redshift. We finally briefly discuss the consequences of such a high local rate of GRB 980425-like events for the future prospects of detecting non-electromagnetic radiation, especially gravitational waves.

Waxman 2004 GRB 980425的射电辐射的偏轴解释

主要内容:
GRB 980425的暴本身的流量很低，一种解释是偏轴观测。如果这样的话，在一年以后的射电辐射应该会很亮（就像GRB 970508, (970508的晚期射电很亮吗？它被确认是一个偏轴观测的暴吗？)）。不过实际射电观测SN 1998bw比预计的流量低三个量级，作者归结为环境的影响。

同样建议对近处的超新星的射电进行普查。

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Title:		The Nature of GRB 980425 and the Search for Off-Axis Gamma-Ray Burst Signatures in Nearby Type Ib/c Supernova Emission
Authors:		Waxman, Eli
Publication:		The Astrophysical Journal, Volume 602, Issue 2, pp. 886-891. (ApJ Homepage)
Publication Date:		02/2004
Bibliographic Code:		2004ApJ...602..886W

Abstract

The identification of Type Ib/c supernovae (SNe Ib/c) as gamma-ray burst (GRB) progenitors is motivated by the association of GRB 980425 with SN 1998bw and of GRB 030329 with SN 2003dh. While the gamma-ray luminosity of GRB 030329 was typical to cosmological GRBs, the luminosity of the nearby (40 Mpc) GRB 980425 was ~5 orders of magnitude lower. The large luminosity difference is commonly explained by hypothesizing either that SNe Ib/c produce two different classes of GRBs or that GRB 980425 was a typical cosmological GRB jet viewed off-axis. In the latter scenario, strong radio emission, L_ν~10³⁰ν^-1/2_10GHz ergs s^-1 Hz^-1, is expected at ~1 yr delay as a result of jet deceleration to subrelativistic speed, as observed from GRB 970508. The radio luminosity of SN 1998bw was 3 orders of magnitude lower than this value. We show that the low radio flux may be consistent with the off-axis jet interpretation, if the density of the wind surrounding the progenitor is lower than typically expected, m≡(M/10^-5M_solaryr^-1)/(v_w/10³kms^-1)~=0.1 instead of m>~1. The lower value of m is consistent with the observed radio emission from the SN shock driven into the wind. This interpretation predicts transition to subrelativistic expansion at ~10 yr delay, with current ~1 mJy 10 GHz flux and m_V~23 optical flux, and with ~10 mas angular source size. It also implies that in order to search for the signature of off-axis GRBs associated with nearby SNe Ib/c, follow-up observations should be carried out on a multiyear timescale.

Chevalier 2006 射电波段的超新星和伽玛暴的成协

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astro-ph/0612734 [abs, ps, pdf, other] :

Title: Circumstellar Interaction Around Type Ib/c Supernovae and the GRB Connection
Authors: R. A. Chevalier
Comments: 8 pages, to appear in Circumstellar Media and Late Stages of Massive Stellar Evolution, RevMexAA

Radio observations of Type Ib/c supernovae suggest that circumstellar interaction takes place with a wide range of wind densities, comparable to that seen in Galactic Wolf-Rayet stars. Efficient production of magnetic field in the shocked region is needed. The X-ray emission observed from some Type Ib/c supernovae is higher than would be expected by the thermal or inverse Compton mechanisms; a synchrotron interpretation requires a flattening of the electron energy spectrum at high energies, as might occur in a cosmic ray dominated shock wave. The wind density variations that are indicated in two supernovae may be due to a binary companion, although variable mass loss from a single star remains a possibility. Other than the optical supernova radiation, the emission from the nearby SN 2006aj/GRB 060218 appears to be powered by a central engine, while that from SN 1998bw/GRB 980425 could be powered by either a central engine or the outer supernova ejecta.