Orbital Elements of 2004 Perseid Meteoroids Perturbed by Jupiter

Jupiter and Saturn produce important gravitational impulses on meteoroids released by comet 109P/Swift-Tuttle. The meteoroids from this comet once released follow retrograde orbits that during their periodic approaches to these planets (within 1.6 and 0.9 A.U., respectively) are impulsed gaining orbital energy. This perturbation effect is translated into a net inward shift in the node of the perturbed meteoroids. Such geometry with Jupiter occurred in 2004 over a meteoroid trail ejected by this comet during the 1862 A.D. return of the comet to perihelion. In order to study the predicted outburst produced by one-revolution meteoroids, the Spanish Photographic Meteor Network (SPMN) performed an extensive campaign. As a part of this observational effort here are presented 10 accurate meteoroid orbits. We discuss their origin by comparing them with the theoretical orbital elements of the dust trails intercepting the Earth during the 2004 Perseid return.     

Determination of Meteoroid Orbits and Spatial Fluxes by Using High-Resolution All-Sky CCD Cameras

By using high-resolution, low-scan-rate, all-sky CCD cameras, the SPanish Meteor Network (SPMN) is currently monitoring meteor and fireball activity on a year round basis. Here are presented just a sampling of the accurate trajectory, radiant and orbital data obtained for meteors imaged simultaneously from two SPMN stations during the continuous 2006–2007 coverage of meteor and fireball monitoring. Typical astrometric uncertainty is 1–2 arc min, while velocity determination errors are of the order of 0.1–0.5 km/s, which is dependent on the distance of each event to the station and its particular viewing geometry. The cameras have demonstrated excellent performance for detecting meteor outbursts. The recent development of automatic detection software is also providing real-time information on the global meteor activity. Finally, some examples of the all-sky CCD cameras applications for detecting unexpected meteor activity are given.     

Study of envelope velocity evolution of core-collapse type Ib-c supernovae from observations of XRF 080109 / SN 2008D and GRB 060218 / SN 2006aj with BTA

Results of modeling the spectra of two supernovae SN2008D and SN2006aj related to the X-ray flash XRF 080109 and gamma-ray burst GRB/XRF 060218, respectively, are studied. The spectra were obtained with the 6-meter BTA telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences in 6.48 and 27.61 days after the explosion of SN2008D, and in 2.55 and 3.55 days after the explosion of SN2006aj. The spectra were interpreted in the Sobolev approximation with the SYNOW code. An assumption about the presence of envelopes around the progenitor stars is confirmed by an agreement between the velocities of lines interpreted as hydrogen and helium, and the empiric power-law velocity drop with time for the envelopes of classic core-collapse supernovae. Detection of a P Cyg profile of the Hβ line in the spectra of optical afterglows of GRBs can be a determinative argument in favor of this hypothesis.     

Gamma ray burst studies with THESEUS

Gamma-ray Bursts (GRBs) are the most powerful transients in the Universe, over–shining for a few seconds all other γ-ray sky sources. Their emission is produced within narrowly collimated relativistic jets launched after the core–collapse of massive stars or the merger of compact binaries. THESEUS will open a new window for the use of GRBs as cosmological tools by securing a statistically significant sample of high-z GRBs, as well as by providing a large number of GRBs at low–intermediate redshifts extending the current samples to low luminosities. The wide energy band and unprecedented sensitivity of the Soft X-ray Imager (SXI) and X-Gamma rays Imaging Spectrometer (XGIS) instruments provide us a new route to unveil the nature of the prompt emission. For the first time, a full characterisation of the prompt emission spectrum from 0.3 keV to 10 MeV with unprecedented large count statistics will be possible revealing the signatures of synchrotron emission. SXI spectra, extending down to 0.3 keV, will constrain the local metal absorption and, for the brightest events, the progenitors’ ejecta composition. Investigation of the nature of the internal energy dissipation mechanisms will be obtained through the systematic study with XGIS of the sub-second variability unexplored so far over such a wide energy range. THESEUS will follow the spectral evolution of the prompt emission down to the soft X–ray band during the early steep decay and through the plateau phase with the unique ability of extending above 10 keV the spectral study of these early afterglow emission phases.

     

BeppoSAX observations of GRS 1915+105

The galactic superluminal source GRS 1915+105 was observed byBeppoSAX at several occasions from October 1996 to April 2000. In April 1999 the 2–10 keV light curve showed a long series of quasi regular pulses with a recurrence time of about 50 s. Some preliminary results of a spectral analysis are presented.     

The Spanish fireball network

Josep M Trigo-Rodríguez, Jordi Llorca, Alberto J Castro-Tirado, José L Ortiz, José A Docobo and Juan Fabregat describe their interdisciplinary approach to minor bodies in the solar system.     

Stellar-wind envelope around the massive supernova progenitor XRF/GRB 060218/SN 2006aj

The spectra of the supernova SN 2006aj identified with the X-ray flash (XRF) and gammaray burst XRF/GRB 060218/SN 2006aj taken with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences are found to exhibit features, which can be interpreted as hydrogen lines. Such features indicate the existence of a stellar-wind envelope around the massive star—the progenitor of the gamma-ray burst. The results of our modeling of two early spectra taken with the 6-m telescope 2.55 and 3.55 days after the explosion of the type-Ic supernova SN 2006aj (z=0.0331) are reported. The spectra are modeled in the Sobolev approximation using SYNOW code [1, 2]. The spectra of the optical afterglow of the X-ray flash XRF/GRB 060218 are found to exhibit spectral features, which can be interpreted as: (1) the P Cyg-profile of the Hα line for the velocity of 33000 km/s—a broad and small deformation of the continuum in the wavelength interval 5600–6600Å for the first epoch (2.55 days) and (2) a part of the P Cyg-profile of the Hα line in absorption blueshifted by 24000 km/s—a broad spectral feature with a minimum at 6100Å (rest wavelength) for the second epoch (3.55 days). Given earlier observations made with the 6-m telescope and the spectra taken with other telescopes (ESO Lick, ESO VLT and NOT) prior to February 23, 2006, it can be concluded that we are observing the evolution of optical spectra of the type Ic massive supernova SN2006aj during its transition from the short phase with the “shock breakout” into the external layers of the stellar-wind envelope to the spectra of the phase of rising supernova luminosity, which corresponds to radiative heating. We are the first to observe the signs of hydrogen in the spectra of a gamma-ray afterglow.     

Study of WATCH GRB error boxes

We have studied the first WATCH GRB Catalogue of-ray Bursts in order to find correlations between WATCH GRB error boxes and a great variety of celestial objects present in 33 different catalogues. No particular class of objects has been found to be significantly correlated with the WATCH GRBs.     

Identification of the donor in GRS 1915+105

This paper describes the results of the MINISAT-01mission after two year in orbit since the launch on April 21^st of1997. It also describes the MINISAT-01 behavior during these years anddescribes, the evolution of the Satellite, by subsystems. Graphics of themost important parameters will be shown to display the difference betweenthe beginning of life and two years after.The paper details the most important events during the Satellite's life suchas the battery overcharge, temperature evolution, onboard computer reset,software updating, and communication failures.     

The Development of the Spanish Fireball Network Using a New All-Sky CCD System

We have developed an all-sky charge coupled devices (CCD) automatic system for detecting meteors and fireballs that will be operative in four stations in Spain during 2005. The cameras were developed following the BOOTES-1 prototype installed at the El Arenosillo Observatory in 2002, which is based on a CCD detector of 4096 × 4096 pixels with a fish-eye lens that provides an all-sky image with enough resolution to make accurate astrometric measurements. Since late 2004, a couple of cameras at two of the four stations operate for 30 s in alternate exposures, allowing 100% time coverage. The stellar limiting magnitude of the images is +10 in the zenith, and +8 below ~ 65° of zenithal angle. As a result, the images provide enough comparison stars to make astrometric measurements of faint meteors and fireballs with an accuracy of ~ 2°arcminutes. Using this prototype, four automatic all-sky CCD stations have been developed, two in Andalusia and two in the Valencian Community, to start full operation of the Spanish Fireball Network. In addition to all-sky coverage, we are developing a fireball spectroscopy program using medium field lenses with additional CCD cameras. Here we present the first images obtained from the El Arenosillo and La Mayora stations in Andalusia during their first months of activity. The detection of the Jan 27, 2003 superbolide of ± 17 ± 1 absolute magnitude that overflew Algeria and Morocco is an example of the detection capability of our prototype.