1,547 research outputs found
The 2011 October Draconids Outburst. II. Meteoroid Chemical Abundances from Fireball Spectroscopy
On October 8, 2011 the Earth crossed dust trails ejected from comet
21P/Giacobini-Zinner in the late 19th and early 20th Century. This gave rise to
an outburst in the activity of the October Draconid meteor shower, and an
international team was organized to analyze this event. The SPanish Meteor
Network (SPMN) joined this initiative and recorded the October Draconids by
means of low light level CCD cameras. In addition, spectroscopic observations
were carried out. Tens of multi-station meteor trails were recorded, including
an extraordinarily bright October Draconid fireball (absolute mag. -10.5) that
was simultaneously imaged from three SPMN meteor ob-serving stations located in
Andalusia. Its spectrum was obtained, showing a clear evolution in the relative
intensity of emission lines as the fireball penetrated deeper into the
atmosphere. Here we focus on the analysis of this remarkable spectrum, but also
discuss the atmospheric trajectory, atmospheric penetration, and orbital data
computed for this bolide which was probably released during
21P/Giacobini-Zinner return to perihelion in 1907. The spectrum is discussed
together with the tensile strength for the October Draconid meteoroids. The
chemical profile evolution of the main rocky elements for this extremely bright
bolide is compared with the elemental abundances obtained for 5 October
Draconid fireballs also recorded during our spectroscopic campaign but observed
only at a single station. Significant chemical heterogeneity between the small
meteoroids is found as we should expect for cometary aggregates being formed by
diverse dust components.Comment: Manuscript in press in Monthly Notices of the Royal Astronomical
Society. Accepted for publication in MNRAS on April 28th, 2013 Manuscript
Pages: 28 Tables: 5 Figures: 12. Manuscript associated: "The 2011 October
Draconids outburst. I. Orbital elements, meteoroid fluxes and
21P/Giacobini-Zinner delivered mass to Earth" by Trigo-Rodriguez et al. is
also in press in the same journa
Observational constraints on the afterglow of GRB 020531
We present the data acquired by the TAROT automated observatory on the
afterglow of GRB 020531. Up to now, no convincing afterglow emission has been
reported for this short/hard GRB at any wavelength, including X-ray and
optical. The combination of our early limits, with other published data allows
us to put severe constraints on the afterglow magnitude and light curve. The
limiting magnitude is 18.5 in R band, 88 minutes after the GRB, and the decay
slope power law index could be larger than 2.2.Comment: 4 pages, submitted to A&A (letter
Follow-up of X-ray transients detected by SWIFT with COLORES using the BOOTES network
The Burst Observer and Optical Transient Exploring System (BOOTES) is a
network of telescopes that allows the continuous monitoring of transient
astrophysical sources. It was originally devoted to the study of the optical
emission from gamma-ray bursts (GRBs) that occur in the Universe. In this paper
we show the initial results obtained using the spectrograph COLORES (mounted on
BOOTES-2), when observing compact objects of diverse nature.Comment: 6 pages, 2 figues, to appear in "Swift: 10 years of discovery",
Proceedings of Scienc
INTEGRAL observation of 3EG J1736-2908
The possible identification by INTEGRAL of the EGRET source 3EG J1736-2908
with the active galactic nucleus GRS 1734-292 is discussed. The latter was
discovered in 1990 and later identified with a Seyfert 1 galaxy. At the time of
the compilation of the 3rd EGRET Catalog, it was not considered as a possible
counterpart of the source 3EG J1736-2908, which remained unidentified. A
detailed multiwavelength study of the EGRET error circle is presented, by
including archival radio, soft- and hard-X observations, suggesting that GRS
1734-292 could be a likely counterpart of 3EG J1736-2908, even though this
poses very interesting questions about the production mechanisms of gamma-rays
with energies greater than 100 MeV.Comment: 6 pages, 3 figures. Accepted for publication on A&A Main Journa
Gamma-Ray Burst 980329 and its X-Ray Afterglow
GRB 980329 is the brightest gamma-ray burst detected so far with the Wide
Field Cameras aboard BeppoSAX, both in gamma-rays and X-rays. With respect to
its fluence (2.6 X 10**-5 erg/s/cm**2 in 50 to 300 keV) it would be in the top
4% of gamma-ray bursts in the 4B catalog (Meegan et al. 1998). The
time-averaged burst spectrum from 2 to 20 and 70 to 650 keV can be well
described by the empirical model of Band et al. (1993). The resulting photon
index above the break energy is exceptionally hard at -1.32 +/- 0.03. An X-ray
afterglow was detected with the narrow-field instruments aboard BeppoSAX 7 h
after the event within the error box as determined with the Wide Field Cameras.
Its peak flux is (1.4 +/- 0.2) X 10**-12 erg/s/cm**2 (2 to 10 keV). The
afterglow decayed according to a power law function with an index of -1.35 +/-
0.03. GRB 980329 is characterized by being bright and hard, and lacking strong
spectral evolution.Comment: 13 pages with 3 figures. Accepted for publication in ApJ Let
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