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Your search keyword '"Mirabel, F."' showing total 4 results
Start Over Author "Mirabel, F." Journal astronomy and astrophysics
4 results on '"Mirabel, F."'

1. UVES/VLT high resolution spectroscopy of GRB 050730 afterglow: probing the features of the GRB environment*

Author

D'Elia, V., Fiore, F., Meurs, E. J. A., Chincarini, G., Melandri, A., Norci, L., Pellizza, L., Perna, R., Piranomonte, S., Sbordone, L., Stella, L., Tagliaferri, G., Vergani, S. D., Ward, P., Angelini, L., Antonelli, L. A., Burrows, D. N., Campana, S., Capalbi, M., Cimatti, A., Costa, E., Cusumano, G., Della Valle, M., Filliatre, P., Fontana, A., Frontera, F., Fugazza, D., Gehrels, N., Giannini, T., Giommi, P., Goldoni, P., Guetta, D., Israel, G., Lazzati, D., Malesani, D., Marconi, G., Mason, K., Mereghetti, S., Mirabel, F., Molinari, E., Moretti, A., Nousek, J., Perri, M., Piro, L., Stratta, G., Testa, V., Vietri, M., D'Elia, V., Fiore, F., Meurs, E. J. A., Chincarini, G., Melandri, A., Norci, L., Pellizza, L., Perna, R., Piranomonte, S., Sbordone, L., Stella, L., Tagliaferri, G., Vergani, S. D., Ward, P., Angelini, L., Antonelli, L. A., Burrows, D. N., Campana, S., Capalbi, M., Cimatti, A., Costa, E., Cusumano, G., Della Valle, M., Filliatre, P., Fontana, A., Frontera, F., Fugazza, D., Gehrels, N., Giannini, T., Giommi, P., Goldoni, P., Guetta, D., Israel, G., Lazzati, D., Malesani, D., Marconi, G., Mason, K., Mereghetti, S., Mirabel, F., Molinari, E., Moretti, A., Nousek, J., Perri, M., Piro, L., Stratta, G., Testa, V., and Vietri, M.

Abstract

Aims.The aim of this paper is to study the Gamma Ray Burst (GRB) environment through the analysis of the optical absorption features due to the gas surrounding the GRB.

Published
2007
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2. INTEGRAL observation of 3EG J1736-2908*

Author

Di Cocco, G., Foschini, L., Grandi, P., Malaguti, G., Castro-Tirado, A. J., Chaty, S., Dean, A. J., Gehrels, N., Grenier, I., Hermsen, W., Kuiper, L., Lund, N., Mirabel, F., Di Cocco, G., Foschini, L., Grandi, P., Malaguti, G., Castro-Tirado, A. J., Chaty, S., Dean, A. J., Gehrels, N., Grenier, I., Hermsen, W., Kuiper, L., Lund, N., and Mirabel, F.

Abstract

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 GRS1734-292 could be a likely counterpart of 3EG J1736-2908, even though this poses very interesting questions about the production mechanisms of γ-rays with energies greater than 100 MeV.

Published
2004
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3. GRB 020813: Polarization in the case of a smooth optical decay*

Author

Gorosabel, J., Rol, E., Covino, S., Castro-Tirado, A. J., Castro Cerón, J. M., Lazzati, D., Hjorth, J., Malesani, D., Della Valle, M., Alighieri, S. di Serego, Fiore, F., Fruchter, A. S., Fynbo, J. P. U., Ghisellini, G., Goldoni, P., Greiner, J., Israel, G. L., Kaper, L., Kawai, N., Klose, S., Kouveliotou, C., Le Floc'h, E., Masetti, N., Mirabel, F., Møller, P., Ortolani, S., Palazzi, E., Pian, E., Rhoads, J., Ricker, G., Saracco, P., Stella, L., Tagliaferri, G., Tanvir, N., van den Heuvel, E., Vietri, M., Vreeswijk, P. M., Wijers, R. A. M. J., Zerbi, F. M., Gorosabel, J., Rol, E., Covino, S., Castro-Tirado, A. J., Castro Cerón, J. M., Lazzati, D., Hjorth, J., Malesani, D., Della Valle, M., Alighieri, S. di Serego, Fiore, F., Fruchter, A. S., Fynbo, J. P. U., Ghisellini, G., Goldoni, P., Greiner, J., Israel, G. L., Kaper, L., Kawai, N., Klose, S., Kouveliotou, C., Le Floc'h, E., Masetti, N., Mirabel, F., Møller, P., Ortolani, S., Palazzi, E., Pian, E., Rhoads, J., Ricker, G., Saracco, P., Stella, L., Tagliaferri, G., Tanvir, N., van den Heuvel, E., Vietri, M., Vreeswijk, P. M., Wijers, R. A. M. J., and Zerbi, F. M.

Abstract

We present the results of a VLT polarimetric monitoring campaign of the GRB 020813 optical afterglow carried out in three nights, from 0.88 to 4.20 days after the gamma-ray event. The mean values of the degree of linear polarization (P) and its position angle (θ) resulting from our campaign are $\langle P\rangle=1.18 \pm 0.10 \%$and $\langle \theta\rangle = 148.7^{\circ} \pm 2.3^{\circ}$, after correcting for Galactic interstellar polarization. Our VLT data set is most naturally described by a constant degree of linear polarization and position angle, nonetheless a slow θevolution cannot be entirely ruled out by our data. The VLT monitoring campaign did not reveal either a significant θrotation respect to the Keck spectropolarimetric observations performed ~0.25 days after the GRB (Barth et al. [CITE]). However, $\langle P\rangle $is a factor of two lower than the polarization degree measured from Keck. Additionally, the VLT polarization data allowed us to construct an accurate V-band light curve. The V-band photometric data revealed a smooth light curve with a break located between the last Keck and our first VLT polarimetric measurement, $0.33 < t_{{\rm break}, V} < 0.88$days after the GRB. The typical magnitude fluctuations of the VLT V-band lightcurve are 0.003 mag, 0.010 mag and 0.016 mag for our three observing nights, respectively. We speculate that the stability of θmight be related to the smoothness of the light curve.

Published
2004
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4. On the jet structure and magnetic field configuration of GRB 020813*

Author

Lazzati, D., Covino, S., Gorosabel, J., Rossi, E., Ghisellini, G., Rol, E., Castro Cerón, J. M., Castro-Tirado, A. J., Della Valle, M., Alighieri, S. di Serego, Fruchter, A. S., Fynbo, J. P. U., Goldoni, P., Hjorth, J., Israel, G. L., Kaper, L., Kawai, N., Le Floc'h, E., Malesani, D., Masetti, N., Mazzali, P., Mirabel, F., Møller, P., Ortolani, S., Palazzi, E., Pian, E., Rhoads, J., Ricker, G., Salmonson, J. D., Stella, L., Tagliaferri, G., Tanvir, N., van den Heuvel, E., Wijers, R. A. M. J., Zerbi, F. M., Lazzati, D., Covino, S., Gorosabel, J., Rossi, E., Ghisellini, G., Rol, E., Castro Cerón, J. M., Castro-Tirado, A. J., Della Valle, M., Alighieri, S. di Serego, Fruchter, A. S., Fynbo, J. P. U., Goldoni, P., Hjorth, J., Israel, G. L., Kaper, L., Kawai, N., Le Floc'h, E., Malesani, D., Masetti, N., Mazzali, P., Mirabel, F., Møller, P., Ortolani, S., Palazzi, E., Pian, E., Rhoads, J., Ricker, G., Salmonson, J. D., Stella, L., Tagliaferri, G., Tanvir, N., van den Heuvel, E., Wijers, R. A. M. J., and Zerbi, F. M.

Abstract

The polarization curve of GRB 020813 is discussed and compared to different models for the structure, evolution and magnetisation properties of the jet and the interstellar medium onto which the fireball impacts. GRB 020813 is best suited for this kind of analysis for the smoothness of its afterglow light curve, ensuring the applicability of current models. The polarization dataset allows us to rule out the standard GRB jet, in which the energy and Lorentz factor have a well defined value inside the jet opening angle and the magnetic field is generated at the shock front. We explore alternative models finding that a structured jet or a jet with a toroidal component of the magnetic field can fit equally well the polarization curve. Stronger conclusions cannot be drawn due to the incomplete sampling of the polarization curve. A more dense sampling, especially at early times, is required to pin down the structure of the jet and the geometry of its magnetic field.

Published
2004
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