Search Publications
Constraining the mass of the GRB 030329 progenitor
Hayes, Matthew; Östlin, Göran; Sollerman, Jesper +2 more
The long-duration gamma-ray burst (GRB) GRB 030329, associated with the supernova (SN) SN 2003dh, occurred inside a star-forming dwarf galaxy at redshift z = 0.1685. The low redshift, and a rich set of archival Hubble Space Telescope (HST) images, makes this GRB well suited for a detailed study of the stellar population in the immediate vicinity o…
A Giant Metrewave Radio Telescope Multifrequency Radio Study of the Isothermal Core of the Poor Galaxy Cluster AWM 4
Raychaudhury, Somak; Clarke, Tracy E.; Mazzotta, Pasquale +7 more
We present a detailed radio morphological study and spectral analysis of the wide-angle tail radio source 4C +24.36 associated with the dominant galaxy in the relaxed galaxy cluster AWM 4. Our study is based on new high-sensitivity GMRT observations at 235, 327, and 610 MHz and on literature and archival data at other frequencies. We find that the…
Independent Emission and Absorption Abundances for Planetary Nebulae
Zhang, Yong; Jenkins, Edward B.; Phillips, Mark +4 more
Emission-line abundances have been uncertain for more than a decade due to unexplained discrepancies in the relative intensities of the forbidden lines and weak permitted recombination lines in PNe and H II regions. The observed intensities of forbidden and recombination lines originating from the same parent ion differ from their theoretical valu…
Unveiling the Narrow-Line Seyfert 1 Nature of Markarian 573 Using Near-Infrared Spectroscopy
Pérez García, A. M.; Acosta-Pulido, J. A.; González-Martín, O. +1 more
In this Letter we present clear evidence that Mrk 573 is an obscured narrow-line Seyfert 1 (NLSy1) galaxy and not an archetypal Seyfert 2, as it has been classified until now. Only three galaxies have been proposed as members of this class, prior to this work. Here we report near-infrared spectroscopic data taken with LIRIS on the 4.2 m William He…
Saturn kilometric radiation as a monitor for the solar wind?
Dougherty, M. K.; Kurth, W. S.; McComas, D. J. +9 more
Since the Voyager mission it is known that Saturn Kilometric Radiation (SKR) is strongly influenced by external forces, i.e., the solar wind and in particular the solar wind ram pressure. Recent studies using Cassini data essentially confirmed these findings for particular periods during the first Cassini orbit of Saturn. The data coverage of SKR …
Major solar energetic particle events of solar cycles 22 and 23: Intensities above the streaming limit
Lario, D.; Aran, A.; Decker, R. B.
Large solar energetic particle (SEP) events constitute a serious radiation hazard to astronauts and spacecraft systems. It is essential to determine the highest particle intensities reached in SEP events, especially at the energies that pose serious risks to human health and spacecraft performance. It has been argued that the highest particle inte…
Interplanetary coronal mass ejections that are undetected by solar coronagraphs
Simnett, G. M.; Howard, T. A.
From February 2003 to September 2005 the Solar Mass Ejection Imager on the Coriolis spacecraft detected 207 interplanetary coronal mass ejections (ICME) in the inner heliosphere. We have examined the data from the Large Angle Spectroscopic Coronagraph (LASCO) on the SOHO spacecraft for evidence of coronal transient activity that might have been th…
V5116 Sagittarii, an Eclipsing Supersoft Postoutburst Nova?
Greiner, J.; Hernanz, M.; Sala, G. +1 more
V5116 Sgr (Nova Sgr 2005 No. 2), discovered on 2005 July 4, was observed with XMM-Newton in 2007 March, 20 months after the optical outburst. The X-ray spectrum shows that the nova had evolved to a pure supersoft X-ray source, with no significant emission at energies above 1 keV. The X-ray light curve shows abrupt decreases and increases of the fl…
Observation and modelling of main-sequence stellar chromospheres - VII. Rotation and metallicity of dM1 stars
Houdebine, E. R.
We have measured v sini and metallicity from high-resolution spectroscopic observations of a selected sample of dM1-type stars.
To measure v sini, we first selected three template stars known for their slow rotation or their very low activity levels and then cross-correlated their spectra with those of our target stars. The excess broadening …A Parameterization Study of the Properties of the X-Ray Dips in the Low-Mass X-Ray Binary X1916-053
Hu, Chin-Ping; Chou, Yi; Chung, Yi-Ying
The ultracompact low-mass X-ray binary X1916-053, which is composed of a neutron star and a semidegenerate white dwarf, exhibits periodic X-ray dips of variable width and depth. We have developed a new method to parameterize this dipping behavior to systematically study its variations. This can help in further understanding binary and accretion di…