97 research outputs found
Kiso observations for 20 GRBs in HETE-2 era
We have established a GRB follow-up observation system at Kiso observatory
(Japan) in 2001. Since the east Asian area had been blank for the GRB follow-up
observational network, this observational system is very important in studying
the temporal and spectral evolution of early afterglows. Using this system, we
have performed quick observations for optical afterglows from early phase based
on HETE-2 and INTEGRAL alerts. Thanks to the quick follow-up observation
system, we have been able to use the Kiso observatory in 20 events, and conduct
their follow-up observations in optical and near infrared wavelengths.Comment: 5 pages, 4 figure. Accepted for publication into "il nuovo cimento".
Proceeding of the 4th Rome GRB conference, eds. L. Piro, L. Amati, S. Covino,
B. Gendr
Early (0.3 day) R-band light curve of the optical afterglow of GRB030329
We observed the optical afterglow of the bright gamma-ray burst GRB030329 on
the nights of 2003 March 29, using the Kiso observatory (the University of
Tokyo) 1.05 m Schmidt telescope. Data were taken from March 29 13:21:26 UT to
17:43:16 (0.072 to 0.253 days after the burst), using an -band filter. The
obtained -band light curve has been fitted successfully by a single power
law function with decay index of . These results remain
unchanged when incorporating two early photometric data points at 0.065 and
0.073 days, reported by Price et al.(2003) using the SSO 40 inch telescope, and
further including RTT150 data (Burenin et al. 2003) covering at about 0.3 days.
Over the period of 0.065-0.285 days after the burst, any deviation from the
power-law decay is smaller than 0.007 mag. The temporal structure reported
by Uemura et al. (2003) does not show up in our -band light curve.Comment: 9 pages, 2 figures, 1 table, accepted for publication in ApJ
Multi-band optical follow-up observations of GRB 020813 at KISO and Bisei observatories
Observations were made of the optical afterglow of GRB020813 (Fox, Blake &
Price, 2002) with the KISO observatory 1.05 m Schmidt telescope and the Bisei
astronomical observatory 1.01 m telescope. Four-band (, and )
photometric data points were obtained from 2002, August 13 10:52 to 16:46 UT,
or 0.3460.516 days after the burst. In order to investigate the early-time
(1 day) evolution of the afterglow, four-band light curves were produced by
analyzing the data taken at these two astronomical observatories, as well as
publicly released data taken by the Magellan Baade telescope (Gladders and
Hall, 2002c). The light curves can be approximated by a broken power law, of
which the indices are approximately 0.46 and 1.33 before and after a break at
0.2 days, respectively. The optical spectral index stayed approximately
constant at 0.9 over 0.17 4.07 days after the burst. Since the
temporal decay index after the break and the spectral index measured at that
time are both consistent with those predicted by a spherical expansion model,
the early break is unlikely to be a jet break, but likely to represent the end
of an early bump in the light curve as was observed in the optical afterglow of
GRB021004.Comment: 12 pages, 3 figures, 2 tables, accepted for publication in ApJ
Conservation and diversity in expression of candidate genes regulating socially-induced female-male sex change in wrasses
International audienc
Very early multi-color observations of the plateau phase of GRB 041006 afterglow
Observations of the optical afterglow of GRB 041006 with the Kiso Observatory
1.05 m Schmidt telescope, the Lulin Observatory 1.0 m telescope and the
Xinglong Observatory 0.6 m telescope. Three-bands (B, V and R) of photometric
data points were obtained on 2004 October 6, 0.025-0.329 days after the burst.
These very early multi band light curves imply the existence of a color
dependent plateau phase. The B-band light curve shows a clear plateau at around
0.03 days after the burst. The R band light curve shows the hint of a plateau,
or a possible slope change, at around 0.1 days after the burst. The overall
behavior of these multi-band light curves may be interpreted in terms of the
sum of two separate components, one showing a monotonic decay the other
exhibiting a rising and a falling phase, as described by the standard afterglow
model.Comment: 11 pages, 2 figures, Accepted to ApJ Letter
Multi-color Shallow Decay and Chromatic Breaks in the GRB 050319 Optical Afterglow
Multi-wavelength B, V, R, I observations of the optical afterglow of GRB
050319 were performed by the 1.05-m telescope at Kiso Observatory and the 1.0-m
telescope at Lulin Observatory from 1.31 hours to 9.92 hours after the burst.
Our R band lightcurves, combined with other published data, can be described by
the smooth broken power-law function, with = -0.84 0.02 to
= -0.480.03, 0.04 days after the GRB. The optical lightcurves
are characterized by shallow decays-- as was also observed in the X-rays--
which may have a similar origin, related to energy injection. However, our
observations indicate that there is still a puzzle concerning the chromatic
breaks in the R band lightcurve (at 0.04 days) and the X-ray lightcurve (at
0.004 days) that remains to be solved.Comment: 14 pages, 2 figures, accpeted for publication in ApJ
Faint High Latitude Carbon Stars Discovered by the Sloan Digital Sky Survey: Methods and Initial Results
We report the discovery of 39 Faint High Latitude Carbon Stars (FHLCs) from
Sloan Digital Sky Survey commissioning data. The objects, each selected
photometrically and verified spectroscopically, range over 16.6 < r* < 20.0,
and show a diversity of temperatures as judged by both colors and NaD line
strengths. At the completion of the Sloan Survey, there will be many hundred
homogeneously selected and observed FHLCs in this sample. We present proper
motion measures for each object, indicating that the sample is a mixture of
extremely distant (>100 kpc) halo giant stars, useful for constraining halo
dynamics, plus members of the recently-recognized exotic class of very nearby
dwarf carbon (dC) stars. Motions, and thus dC classification, are inferred for
40-50 percent of the sample, depending on the level of statistical significance
invoked. The new list of dC stars presented here, although selected from only a
small fraction of the final SDSS, doubles the number of such objects found by
all previous methods. (Abstract abridged).Comment: Accepted for publication in The Astronomical Journal, Vol. 124, Sep.
2002, 40 pages, 7 figures, AASTeX v5.
In Silico Analysis Reveals 75 Members of Mitogen-Activated Protein Kinase Kinase Kinase Gene Family in Rice
Mitogen-Activated Protein Kinase Kinase Kinases (MAPKKKs) are important components of MAPK cascades, which are universal signal transduction modules and play important role in plant growth and development. In the sequenced Arabidopsis genome 80 MAPKKKs were identified and currently being analysed for its role in different stress. In rice, economically important monocot cereal crop only five MAPKKKs were identified so far. In this study using computational analysis of sequenced rice genome we have identified 75 MAPKKKs. EST hits and full-length cDNA sequences (from KOME or Genbank database) of 75 MAPKKKs supported their existence. Phylogenetic analyses of MAPKKKs from rice and Arabidopsis have classified them into three subgroups, which include Raf, ZIK and MEKK. Conserved motifs in the deduced amino acid sequences of rice MAPKKKs strongly supported their identity as members of Raf, ZIK and MEKK subfamilies. Further expression analysis of the MAPKKKs in MPSS database revealed that their transcripts were differentially regulated in various stress and tissue-specific libraries
DISCOVERY OF DRAMATIC OPTICAL VARIABILITY IN SDSS J1100+4421: A PECULIAR RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXY?
We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey (KISS). The source brightened in the optical by at least a factor of three within about half a day. Spectroscopic observations suggest that this object is likely a narrow-line Seyfert 1 galaxy (NLS1) at z=0.840, however with unusually strong narrow emission lines. The estimated black hole mass of ~ 10^7 Msun implies bolometric nuclear luminosity close to the Eddington limit. SDSS J1100+4421 is also extremely radio-loud, with a radio loudness parameter of R ~ 4 x 10^2 - 3 x 10^3, which implies the presence of relativistic jets. Rapid and large-amplitude optical variability of the target, reminiscent of that found in a few radio- and gamma-ray loud NLS1s, is therefore produced most likely in a blazar-like core. The 1.4 GHz radio image of the source shows an extended structure with a linear size of about 100 kpc. If SDSS J1100+4421 is a genuine NLS1, as suggested here, this radio structure would then be the largest ever discovered in this type of active galaxie
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