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[show abstract]
[hide abstract]
ABSTRACT: (abridged) Recently, a new class of radio transients in the 5-GHz band was detected by Bower et al. We present new deep near-Infrared (IR) observations of the field containing these transients, and find no counterparts down to a limiting magnitude of K=20.4 mag. We argue that the bright (>1 Jy) radio transients recently reported by Kida et al. are consistent with being additional examples of the Bower et al. transients. We refer to these groups of events as "long-duration radio transients". The main characteristics of this population are: time scales longer than 30 minute but shorter than several days; rate, ~10^3 deg^-2 yr^-1; progenitors sky surface density of >60 deg^-2 (95% C.L.) at Galactic latitude ~40 deg; 1.4-5 GHz spectral slopes, f_\nu ~ \nu^alpha, with alpha>0; and most notably the lack of any counterparts in quiescence in any wavelength. We rule out an association with many types of objects. Galactic brown-dwarfs or some sort of exotic explosions remain plausible options. We argue that an attractive progenitor candidate for these radio transients is the class of Galactic isolated old neutron stars (NS). We confront this hypothesis with Monte-Carlo simulations of the space distribution of old NSs, and find satisfactory agreement for the large areal density. Furthermore, the lack of quiescent counterparts is explained quite naturally. In this framework we find: the mean distance to events in the Bower et al. sample is of order kpc; the typical distance to the Kida et al. transients are constrained to be between 30 pc and 900 pc (95% C.L.); these events should repeat with a time scale of order several months; and sub-mJy level bursts should exhibit Galactic latitude dependence. We discuss possible mechanisms giving rise to the observed radio emission. Comment: Submitted to ApJ, 17 pages, 10 figures
10/2009;
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D. A. Perley,
W. Li,
R. Chornock,
J. X. Prochaska,
N. R. Butler,
P. Chandra,
L. K. Pollack,
J. S. Bloom,
A. V. Filippenko,
H. Swan, [......],
T. McKay,
D. Le Mignant,
M. Modjaz,
W. Rujopakarn,
R. Russel,
M. A. Skinner,
G. H. Smith,
I. Smith,
M. A. van Dam,
and S. Yost
[show abstract]
[hide abstract]
ABSTRACT: The optical afterglow of long-duration GRB 071003 is among the brightest yet to be detected from any GRB, with R ≈ 12 mag in KAIT observations starting 42 s after the GRB trigger, including filtered detections during prompt emission. However, our high-S/N afterglow spectrum displays only extremely weak absorption lines at what we argue is the host redshift of z = 1.60435, in contrast to the three other, much stronger Mg II absorption systems observed at lower redshifts. Together with Keck adaptive optics observations, which fail to reveal a host galaxy coincident with the burst position, our observations suggest a halo progenitor and offer a cautionary tale about the use of Mg II for GRB redshift determination. We present early- through late-time observations spanning the electromagnetic spectrum, constrain the connection between the prompt emission and early variations in the light curve (we observe no correlation), and discuss possible origins for an unusual, marked rebrightening that occurs a few hours after the burst: likely either a late-time refreshed shock or a wide-angle secondary jet. Analysis of the late-time afterglow is most consistent with a wind environment, suggesting a massive star progenitor. Together with GRB 070125, this may indicate that a small but significant portion of star formation in the early universe occurred far outside what we consider a normal galactic disk.
The Astrophysical Journal 12/2008; 688(1):470. · 6.02 Impact Factor
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M. M. Kasliwal,
S. B. Cenko,
S. R. Kulkarni,
P. B. Cameron,
E. Nakar,
E. O. Ofek,
A. Rau,
A. M. Soderberg,
S. Campana,
J. S. Bloom, [......],
C. B. Markwardt,
G. Sato,
P. Chandra, D. Frail,
D. B. Fox,
P. A. Price,
E. Berger,
S. A. Grebenev,
R. A. Krivonos,
and R. A. Sunyaev
[show abstract]
[hide abstract]
ABSTRACT: GRB 070610 is a typical high-energy event with a duration of 5 s. Yet within the burst localization we detect a highly unusual X-ray and optical transient, Swift J195509.6+261406. We see high-amplitude X-ray and optical variability on very short timescales even at late times. Using near-infrared imaging assisted by a laser guide star and adaptive optics, we identified the counterpart of Swift J195509.6+261406. Late-time optical and near-infrared imaging constrain the spectral type of the counterpart to be fainter than a K-dwarf, assuming it is of Galactic origin. It is possible that GRB 070610 and Swift J195509.6+261406 are unrelated sources. However, the absence of a typical X-ray afterglow from GRB 070610 in conjunction with the spatial and temporal coincidence of the two motivate us to suggest that the sources are related. The closest (imperfect) analog to Swift J195509.6+261406 is V4641 Sgr, an unusual black hole binary. We suggest that Swift J195509.6+261406 along with V4641 Sgr define a subclass of stellar black hole binaries—the fast X-ray novae. We further suggest that fast X-ray novae are associated with bursts of gamma rays. If so, GRB 070610 defines a new class of celestial gamma-ray bursts and these bursts dominate the long-duration GRB demographics.
The Astrophysical Journal 12/2008; 678(2):1127. · 6.02 Impact Factor
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K. Hurley,
T. Cline,
E. Mazets,
R. Aptekar,
S. Golenetskii,
D. Frederiks, D. Frail,
S. Kulkarni,
J. Trombka,
T. McClanahan,
R. Starr,
and J. Goldsten
[show abstract]
[hide abstract]
ABSTRACT: The extremely energetic (~10-4 ergs cm-2) gamma-ray burst (GRB) of 1999 December 8 was triangulated to an ~14 arcmin2 error box ~1.8 days after its arrival at Earth with the third interplanetary network (IPN), which consists of the Ulysses, Near-Earth Asteroid Rendezvous, and Wind spacecraft. Radio observations with the Very Large Array ~2.7 days after the burst revealed a bright fading counterpart whose position is consistent with that of an optical transient source with a redshift of 0.707. We present the time history, peak flux, fluence, and refined 1.3 arcmin2 error box of this event and discuss its energetics. This is the first time that a counterpart has been found for a GRB localized only by the IPN.
The Astrophysical Journal 12/2008; 534(1):L23. · 6.02 Impact Factor
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M. M. Kasliwal,
S. B. Cenko,
S. R. Kulkarni,
P. B. Cameron,
E. Nakar,
E. O. Ofek,
A. Rau,
A. M. Soderberg,
S. Campana,
J. S. Bloom, [......],
C. B. Markwardt,
G Sato,
P Chandra, D. Frail,
D. B. Fox,
P. Price,
E. Berger,
S. A. Grebenev,
R. A. Krivonos,
R. A. Sunyaev
[show abstract]
[hide abstract]
ABSTRACT: GRB 070610 is a typical high-energy event with a duration of 5s.Yet within the burst localization we detect a highly unusual X-ray and optical transient, SwiftJ195509.6+261406. We see high amplitude X-ray and optical variability on very short time scales even at late times. Using near-infrared imaging assisted by a laser guide star and adaptive optics, we identified the counterpart of SwiftJ195509.6+261406. Late-time optical and near-infrared imaging constrain the spectral type of the counterpart to be fainter than a K-dwarf assuming it is of Galactic origin. It is possible that GRB 070610 and Swift J195509.6+261406 are unrelated sources. However, the absence of a typical X-ray afterglow from GRB 070610 in conjunction with the spatial and temporal coincidence of the two motivate us to suggest that the sources are related. The closest (imperfect) analog to Swift J195509.6+261406 is V4641 Sgr, an unusual black hole binary. We suggest that Swift J195509.6+261406 along with V4641 Sgr define a sub-class of stellar black hole binaries -- the fast X-ray novae. We further suggest that fast X-ray novae are associated with bursts of gamma-rays. If so, GRB 070610 defines a new class of celestial gamma-ray bursts and these bursts dominate the long-duration GRB demographics Comment: Substantially revised since additional late-time observations indicate the optical/IR counterpart to GRB070610 is very faint. Precise astrometry indicates that the original spectrum was of a very nearby brighter star but not the counterpart to GRB070610. Full resolution figures at http://www.astro.caltech.edu/~mansi/g070610.ps
08/2007;
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A Gal-Yam,
D B Fox,
P A Price,
E O Ofek,
M R Davis,
D C Leonard,
A M Soderberg,
B P Schmidt,
K M Lewis,
B A Peterson, [......],
D-S Moon,
P J Brown,
A Cucchiara,
F Harrison,
T Piran,
S E Persson,
P J McCarthy,
B E Penprase,
R A Chevalier,
A I MacFadyen
[show abstract]
[hide abstract]
ABSTRACT: Over the past decade, our physical understanding of gamma-ray bursts (GRBs) has progressed rapidly, thanks to the discovery and observation of their long-lived afterglow emission. Long-duration (> 2 s) GRBs are associated with the explosive deaths of massive stars ('collapsars', ref. 1), which produce accompanying supernovae; the short-duration (< or = 2 s) GRBs have a different origin, which has been argued to be the merger of two compact objects. Here we report optical observations of GRB 060614 (duration approximately 100 s, ref. 10) that rule out the presence of an associated supernova. This would seem to require a new explosive process: either a massive collapsar that powers a GRB without any associated supernova, or a new type of 'engine', as long-lived as the collapsar but without a massive star. We also show that the properties of the host galaxy (redshift z = 0.125) distinguish it from other long-duration GRB hosts and suggest that an entirely new type of GRB progenitor may be required.
Nature 12/2006; 444(7122):1053-5. · 36.28 Impact Factor
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A. M. Soderberg,
S. R. Kulkarni,
E. Nakar,
E. Berger,
P. B. Cameron,
D. B. Fox, D. Frail,
A. Gal-Yam,
R. Sari,
S. B. Cenko, [......],
G. Pooley,
D.-S. Moon,
B. E. Penprase,
E. Ofek,
A. Rau,
N. Gehrels,
J. A. Nousek,
D. N. Burrows,
S. E. Persson,
P. J. McCarthy
Nature 08/2006; 442(7106):1014-1017. · 36.28 Impact Factor
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A. Gal-Yam,
D. Fox,
P. Price,
M. Davis,
D. Leonard,
A. Soderberg,
E. Nakar,
E. Ofek,
B Schmidt,
K. Lewis, [......],
D. Burrows,
V. Mangano,
S Holland,
P. Brown,
D. -S. Moon,
F. Harrison,
T. Piran,
P. McCarthy,
B. Penprase,
R. Chevalier
[show abstract]
[hide abstract]
ABSTRACT: Over the past decade our physical understanding of gamma-ray bursts (GRBs) has progressed rapidly thanks to the discovery and observation of their long-lived afterglow emission. Long-duration (T < 2 s) GRBs are associated with the explosive deaths of massive stars (``collapsars''), which produce accompanying supernovae, while the short-duration (T > 2 s) GRBs arise from a different origin, which has been argued to be the merger of two compact objects, either neutron stars or black holes. Here we present observations of GRB060614, a 100-s long burst discovered by the Swift satellite, which require the invocation of a new explosive process: either a massive ``collapsar'' that powers a GRB without any associated supernova, or a new type of engine, as long-lived as the collapsar but without any such massive stellar host. We also discuss the properties of this burst's redshift z=0.125 host galaxy, which distinguish it from other long-duration GRBs and suggest that an entirely new type of GRB progenitor may be required.
08/2006;
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[show abstract]
[hide abstract]
ABSTRACT: The nearby (z=0.1685) gamma-ray burst of 29 March 2003 has presented us
with a unique opportunity to study an event with unprecedented clarity.
This burst reached flux density levels at centimeter wavelengths more
than 50 times brighter than any previously studied event. Here we
present the results of VLBI observations that have resolved the radio
afterglow, and constrain its proper motion in the sky to <0.3 mas.
The size of the afterglow is measured to be ˜0.08 mas 24 days
after the burst, consistent with expectations of the standard fireball
model. In observations taken 51 days after the burst we detect an
additional compact, ``jet'', component at a distance from the main
component of 0.28 ± 0.05. The presence of this jet component is
not consistent with the standard model.
11/2005; 340:298.
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Avishay Gal-Yam,
Ehud Nakar,
Eran Ofek,
D. B. Fox,
S. B. Cenko,
S. R. Kulkarni,
A. M. Soderberg,
F. Harrison,
P. A. Price,
B. E. Penprase, D. Frail,
E. Berger,
M. Gladders,
J. Mulchaey
[show abstract]
[hide abstract]
ABSTRACT: The detection of the afterglow emission and host galaxies of short-hard gamma-ray bursts (SHBs) is one of the most exciting recent astronomical discoveries. Indications that SHB progenitors belong to old stellar populations, in contrast to those of the long-soft GRBs, provide a strong clue about their physical nature. Definitive conclusions however are limited by the small number of SHBs with known hosts. Here, we present our investigation of SHBs previously localized by the interplanetary network (IPN) using new and archival optical and X-ray observations. We show that we can likely identify the host galaxies/clusters for additional two bursts, significantly increasing the sample of SHBs with known hosts and/or distances. In particular, we determine that the bright SHB 790613 occurred within the rich galaxy cluster Abell 1892, making it probably the nearest SHB currently known. We show that the brightest galaxy within the error box of SHB 000607, at z=0.14, is most likely the host galaxy of this event. Additionally, we rule out the existence of galaxy overdensities (down to ~21mag) near the locations of two other SHBs, and set a lower limit on their probable redshift. We combine our SHB sample with events discovered recently by the Swift and HETE-2 missions, and investigate the properties of the extended sample. Comparison to SNe Ia shows that the progenitors of SHBs are typically older, implying a typical life time of several Gy. We also show that it is unlikely that there is a significant population of progenitors with life time shorter than 1Gy. This result disfavors the popular model of NS-NS mergers as the progenitors of SHBs. Comment: Revised following comments. Matches version submitted to ApJ
09/2005;
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K. Hurley,
T. Cline,
E. Mazets,
R. Aptekar,
S. Golenetskii,
D. Frederiks, D. Frail,
S. Kulkarni,
J. Trombka,
T. McClanahan,
R. Starr,
J. Goldsten
[show abstract]
[hide abstract]
ABSTRACT: The extremely energetic (~10^-4 erg/cm^2) gamma-ray burst (GRB) of 1999 December 8 was triangulated to a ~14 sq. arcmin. error box ~1.8 d after its arrival at Earth with the 3rd interplanetary network (IPN), consisting of the Ulysses, Near Earth Asteroid Rendezvous (NEAR), and WIND spacecraft. Radio observations with the Very Large Array ~2.7 d after the burst revealed a bright fading counterpart whose position is consistent with that of an optical transient source whose redshift is z=0.707. We present the time history, peak flux, fluence, and refined 1.3 sq. arcmin. error box of this event, and discuss its energetics. This is the first time that a counterpart has been found for a GRB localized only by the IPN. Comment: Revised version, accepted for publication in the Astrophysical Journal Letters
02/2000;
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B ~E Schaefer,
J ~A Snyder,
J Hernandez,
B Roscherr,
M Deng,
N Ellman,
C Bailyn,
A Rengstorf,
D Smith,
A Levine, [......],
H Schenner,
J Shin,
J Sinnott,
S Sofia,
J Stock,
J Suarez,
D Telléria,
B Vicente,
K Vieira,
K Vivas
apjl. 10/1999; 524:L103-L106.
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Bradley E. Schaefer,
J A Snyder,
J Hernandez,
B. Roscherr,
M. Deng,
N. Ellmann,
C. Bailyn,
A. Rengstorf,
D Smith,
A Levine, [......],
S. Muffson,
J Musser,
O. Naranjo,
A. Oemler,
R. Pacheco,
G. Paredes,
M. Rengel,
L Romero,
P. Rosenzweig,
C. Sabbey et al
[show abstract]
[hide abstract]
ABSTRACT: The optical transient of the faint Gamma Ray Burst 990308 was detected by the QUEST camera on the Venezuelan 1-m Schmidt telescope starting 3.28 hours after the burst. Our photometry gives $V = 18.32 \pm 0.07$, $R = 18.14 \pm 0.06$, $B = 18.65 \pm 0.23$, and $R = 18.22 \pm 0.05$ for times ranging from 3.28 to 3.47 hours after the burst. The colors correspond to a spectral slope of close to $f_{\nu} \propto \nu^{1/3}$. Within the standard synchrotron fireball model, this requires that the external medium be less dense than $10^{4} cm^{-3}$, the electrons contain $> 20%$ of the shock energy, and the magnetic field energy must be less than 24% of the energy in the electrons for normal interstellar or circumstellar densities. We also report upper limits of $V > 12.0$ at 132 s (with LOTIS), $V > 13.4$ from 132-1029s (with LOTIS), $V > 15.3$ at 28.2 min (with Super-LOTIS), and a 8.5 GHz flux of $< 114 \mu Jy$ at 110 days (with the Very Large Array). WIYN 3.5-m and Keck 10-m telescopes reveal this location to be empty of any host galaxy to $R > 25.7$ and $K > 23.3$. The lack of a host galaxy likely implies that it is either substantially subluminous or more distant than a red shift of $\sim 1.2$. Comment: ApJ Lett submitted, 5 pages, 2 figures, no space for 12 coauthors
07/1999;
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D. Fox,
P. Price,
A. Soderberg,
E. Berger,
S. Kulkarni,
R. Sari, D. Frail,
F. Harrison,
S. Yost,
K. Matthews,
B. Peterson,
I. Tanaka,
J. Christiansen,
G. Moriarty-Schieven
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D. Frail,
S. Yost,
E. Berger,
F. Harrison,
R. Sari,
S. Kulkarni,
Ginger Taylor,
J. Bloom,
D. Fox,
G. Moriarty-Schieven,
P. Price
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Gamma-Ray Bursts in the Afterglow Era.
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C. Kouveliotou,
S. Dieters,
T. Strohmayer,
J. van Paradijs,
G. J. Fishman,
C. A. Meegan,
K. Hurley,
J. Kommers,
I. Smith, D. Frail,
T. Murakami
Nature · 36.28 Impact Factor
