Is the Gamma Ray Bursts emission suppressed at high energy? (2009)
We compare the luminosity function and rate inferred from the GBM long bursts peak flux distribution with those inferred from the Swift and BATSE peak flux distribution. We find that the GBM, BATSE...
Pian, Elena, Romano, Patrizia, Maoz, Dan, Cucchiara, Antonino, Pagani, Claudio, La Parola, Valentina
We have observed four low-luminosity active galactic nuclei classified as Type 1 LINERs with the X-ray Telescope (XRT) and the UltraViolet-Optical Telescope (UVOT) onboard Swift, in an attempt to...
Pian, Elena, Campana, Sergio, Chincarini, Guido, Corcoran, Michael F., Hamaguchi, Kenji, Gull, Theodore, ...
We observed the massive binary stellar system of Eta Carinae in the 0.3-10 keV energy range with the X-ray Telescope onboard the Swift satellite during the period 15 December 2008 - 11 March 2009,...
Tanaka, Masaomi, Kawabata, Koji S., Yamanaka, Masayuki, Maeda, Keiichi, Hattori, Takashi, Aoki, Kentaro, ...
We present the first spectropolarimetric observations of a candidate of super-Chandrasekhar mass Type Ia supernova (SN): SN 2009dc. The observations were performed at 5.6 and 89.5 days after the...
Simultaneous multi-frequency observations of PG 1553+113 (2009)
Mankuzhiyil, Nijil, Dorner, Daniela, Prandini, Elisa, Persic, Massimo, Collaboration, For The MAGIC, Pian, Elena, ...
We report simultaneous multi-frequency observations of the blazar PG 1553+113, that were carried out in March-April 2008. Optical, X-ray, high-energy (HE; greater than 100 MeV) gamma-ray, and...
Tanaka, Masaomi, Yamanaka, Masayuki, Maeda, Keiichi, Kawabata, Koji S., Hattori, Takashi, Minezaki, Takeo, ...
We present optical spectroscopic and photometric observations of supernova (SN) 2008D, associated with the luminous X-ray transient 080109, at >300 days after the explosion (nebular phases). We also...
Tanaka, Masaomi, Kawabata, Koji S., Maeda, Keiichi, Iye, Masanori, Hattori, Takashi, Pian, Elena, ...
We present an optical spectropolarimetric observation of the unique Type Ib supernova (SN) 2005bf at 8 days after the second maximum. The data, combined with the polarization spectrum taken at 6 days...
A low energy core-collapse supernova without a hydrogen envelope (2009)
Valenti, Stefano, Pastorello, Andrea, Cappellaro, Enrico, Benetti, Stefano, Mazzali, Paolo, Manteca, Jose, ...
The final fate of massive stars depends on many factors, including mass, rotation rate, magnetic fields and metallicity. Theory suggests that some massive stars (initially greater than 25-30 solar...
Tanaka, Masaomi, Yamanaka, Masayuki, Maeda, Keiichi, Kawabata, Koji S., Hattori, Takashi, Minezaki, Takeo, ...
Tanaka, Masaomi, Kawabata, Koji S., Maeda, Keiichi, Iye, Masanori, Hattori, Takashi, Pian, Elena, ...
Vrijhk Photometry of PKS 0537-441 and PKS 2155-304 in 2006-2008 (2008)
Impiombato, Domenico, Tosti, Gino, Treves, Aldo, Covino, Stefano, Pian, Elena, Ciprini, Stefano
We report the 2006-2008 light curves obtained with the REM telescope in VRIJHK bands for the two BL Lac objects PKS 0537-441 and PKS 2155-304
Mazzali, Paolo A., Valenti, Stefano, Della Valle, Massimo, Chincarini, Guido, Sauer, Daniel N., Benetti, Stefano, ...
The only supernovae (SNe) to have shown early gamma-ray or X-ray emission thus far are overenergetic, broad-lined Type Ic SNe (Hypernovae - HNe). Recently, SN 2008D shows several novel features: (i)...
Asphericity in Supernova Explosions from Late-Time Spectroscopy (2008)
Maeda, Keiichi, Kawabata, Koji, Mazzali, Paolo A., Tanaka, Masaomi, Valenti, Stefano, Nomoto, Ken'ichi, ...
Core-collapse supernovae (CC-SNe) are the explosions that announce the death of massive stars. Some CC-SNe are linked to long-duration gamma-ray bursts (GRBs) and are highly aspherical. One important...
Asphericity in supernova explosions from late-time spectroscopy (2008)
Maeda, Keiichi, Kawabata, Koji, Mazzali, Paolo A., Tanaka, Masaomi, Valenti, Stefano, Nomoto, Ken'ichi, ...
Mazzali, Paolo A., Valenti, Stefano, Della Valle, Massimo, Chincarini, Guido, Sauer, Daniel N., Benetti, Stefano, ...
Models for the Type Ic Hypernova SN 2003lw associated with GRB 031203 (2007)
Mazzali, Paolo A., Deng, Jinsong, Pian, Elena, Malesani, Daniele, Tominaga, Nozomu, Maeda, Keiichi, ...
The Gamma-Ray Burst 031203 at a redshift z=0.1055 revealed a highly reddened Type Ic Supernova, SN 2003lw, in its afterglow light. This is the third well established case of a link between a...
Gamma-ray bursts associated with supernovae: a systematic analysis of BATSE GRB candidates (2007)
Bosnjak, Zeljka Marija, Celotti, Annalisa, Ghirlanda, Giancarlo, Della Valle, Massimo, Pian, Elena
We examined the properties of a sample of BATSE Gamma--Ray Bursts (GRBs) comprising events which have indications of association with a supernova (SN), some on the basis of indications of...
On the consistency of the peculiar GRBs 060218 and 060614 with the Ep,i - Eiso correlation (2007)
Amati, Lorenzo, Della Valle, Massimo, Frontera, Filippo, Malesani, Daniele, Guidorzi, Cristiano, Montanari, Enrico, ...
We analyze and discuss the position of GRB 060218 and GRB 060614 in the Ep,i - Eiso plane. GRB 060218 is important because of its similarity with GRB 980425, the proto-type event of the GRB-SN...
INTEGRAL and Swift Observations of Blazars in Outburst (2007)
Pian, Elena, Foschini, Luigi, Ghisellini, Gabriele
The blazars 3C 454.3, PKS 0537-441 and PKS 2155-304 are traditionally known to be among the most active sources of this class. They emit at all frequencies, up to the gamma-rays, and are good probes...
Maeda, Keiichi, Kawabata, Koji, Tanaka, Masaomi, Nomoto, Ken'ichi, Tominaga, Nozomu, Hattori, Takashi, ...
Optical spectroscopy and photometry of SN 2006aj have been performed with the Subaru telescope at t > 200 days after GRB060218, the X-ray Flash with which it was associated. Strong nebular...
Keck and ESO-VLT View of the Symmetry of the Ejecta of the XRF/SN 2006aj (2007)
Mazzali, Paolo A., Foley, Ryan J., Deng, Jinsong, Patat, Ferdinando, Pian, Elena, Baade, Dietrich, ...
Nebular-phase spectra of SN 2006aj, which was discovered in coincidence with X-ray flash 060218, were obtained with Keck in 2006 July and the Very Large Telescope in 2006 September. At the latter...
Mazzali, Paolo A., Foley, Ryan J., Deng, Jinsong, Patat, Ferdinando, Pian, Elena, Baade, Dietrich, ...
Optical observations of GRB 060218/SN 2006aj and its host galaxy (2007)
Ferrero, Patrizia, Palazzi, Eliana, Pian, Elena, Savaglio, Sandra
The host galaxy of GRB 011121: Morphology and Spectral Energy Distribution (2006)
Yoldas, Aybuke Kupcu, Salvato, Mara, Greiner, Jochen, Pierini, Daniele, Pian, Elena, Rau, Arne
(Abridged) We present a detailed study of the host galaxy of GRB 011121 (at z = 0.36) based on high-resolution imaging in 5 broad-band, optical and near-infrared filters with HST and VLT/ISAAC. The...
Optical observations of GRB 060218/SN 2006aj and its host galaxy (2006)
Ferrero, Patrizia, Palazzi, Eliana, Pian, Elena, Savaglio, Sandra
The supernova SN 2006aj associated with GRB 060218 is the second-closest GRB-SN observed to date ($z$=0.033) and is the clearest example of a SN associated with a Swift GRB with the earliest optical...
Levan, Andrew, Fruchter, Andrew, Rhoads, James, Mobasher, Bahram, Tanvir, Nial, Gorosabel, Javier, ...
We present near-infrared (nIR) and optical observations of the afterglow of GRB 030115. Discovered in an infrared search at Kitt Peak 5 hours after the burst trigger, this afterglow is amongst the...
A neutron-star-driven X-ray flash associated with supernova SN 2006aj (2006)
Mazzali, Paolo A., Deng, Jinsong, Nomoto, Ken'ichi, Sauer, Daniel N., Pian, Elena, Tominaga, Nozomu, ...
Supernovae connected with long-duration gamma-ray bursts (GRBs) are hyper-energetic explosion resulting from the collapse of very massive stars (about 40Mo, where Mo is the mass of the Sun) stripped...
Models for the Type Ic Hypernova SN 2003lw associated with GRB 031203 (2006)
Mazzali, Paolo A., Deng, Jinsong, Pian, Elena, Malesani, Daniele, Tominaga, Nozomu, Maeda, Keiichi, ...
The Gamma-Ray Burst 031203 at a redshift z=0.1055 revealed a highly reddened Type Ic Supernova, SN 2003lw, in its afterglow light. This is the third well established case of a link between a...
INTEGRAL observations of the blazar 3C454.3 in outburst (2006)
Pian, Elena, Foschini, Luigi, Beckmann, Volker
In Spring 2005, the blazar 3C454.3 underwent a dramatic outburst at all wavelengths from mm to X-rays. This prompted INTEGRAL observations, accomplished in 15-18 May 2005. The source was detected by...
Models for the type Ic hypernova SN 2003lw associated with GRB 031203 (2006)
Mazzali, Paolo A., Deng, Jingsong, Pian, Elena, Malesani, Daniele, Tominaga, Nozomu, Maeda, Keiichi, ...
A neutron-star-driven X-ray flash associated with supernova SN 2006aj (2006)
Mazzali, Paolo A., Deng, Jinsong, Nomoto, Ken'ichi, Sauer, Daniel N., Pian, Elena, Tominaga, Nozomu, ...
Pian, Elena, Falomo, Renato, Treves, Aldo
The ultraviolet (UV) spectra of 16 blazars ( ~1) from the archives of the Hubble Space Telescope Faint Object Spectrograph have been analyzed in order to study in a systematic way the properties...
An asymmetric energetic type Ic supernova viewed off-axis, and a link to gamma ray bursts (2005)
Mazzali, Paolo A., Kawabata, Koji S., Maeda, Keiichi, Nomoto, Ken'ichi, Filippenko, Alexei V., Ramirez-Ruiz, Enrico, ...
Levan, Andrew, Patel, Sandeep, Kouveliotou, Chryssa, Fruchter, Andrew, Rhoads, James, Rol, Evert, ...
X-ray Flashes (XRFs) are, like Gamma-Ray Bursts (GRBs), thought to signal the collapse of massive stars in distant galaxies. Many models posit that the isotropic equivalent energies of XRFs are lower...
GRB 020410: A Gamma-ray burst afterglow discovered by its supernova light (2004)
Levan, Andrew, Nugent, Peter, Fruchter, Andrew, Burud, Ingunn, Branch, David, Rhoads, James, ...
We present the discovery and monitoring of the optical transient (OT) associated with GRB 020410. The fading OT was found by Hubble Space Telescope (HST) observations taken 28 and 65 days after burst...
A very energetic supernova associated with the gamma-ray burst of 29 March 2003 (2003)
Hjorth, Jens, Sollerman, Jesper, Møller, Palle, Fynbo, Johan P. U., Woosley, Stan E., Kouveliotou, Chryssa, ...
Over the past five years evidence has mounted that long-duration (> 2 s) gamma-ray bursts (GRBs)--the most brilliant of all astronomical explosions--signal the collapse of massive stars in our...
A second glance at SN 2002ap and the M74 field with XMM-Newton (2003)
Soria, Roberto, Pian, Elena, Mazzali, Paolo
We have re-observed the field of M74 in January 2003 with XMM-Newton, 11 months after the X-ray detection of SN 2002ap. From a comparison of the two XMM-Newton observations we obtain more accurate...
A very energetic supernova associated with the γ-ray burst of 29 March 2003 (2003)
Hjorth, Jens, Sollerman, Jesper, Møller, Palle, Fynbo, Johan P. U., Woosley, Stan E., Kouveliotou, Chryssa, ...
Recent highlights in the X-ray study of blazars (2002)
Blazars exhibit flux and spectral variations of largest amplitude at the highest frequencies. Therefore, monitoring their variability at X- and gamma-rays is the most effective tool to peer into the...
X-ray Variability of Blazars (2002)
Critical progress in our understanding of high energy emission from AGN has been determined in the last 10 years by X-ray monitoring campaigns with many space missions, notably ROSAT, ASCA, RXTE,...
Optical Observations of Afterglows (2001)
Optical, infrared and ultraviolet observations of GRB fields have allowed detection of counterparts and host galaxies of the high energy transients, thus crucially contributing to our present...
Since the discovery of Gamma-Ray Bursts (GRBs), attempts have been made to detect correlated optical transient emission from these objects. In January 1999, the ROTSE I robotic telescope detected a...
The metamorphosis of SN1998bw (2001)
Patat, Ferdinando, Cappellaro, Enrico, Danziger, John, Mazzali, Paolo A., Sollerman, Jesper, Augusteijn, Thomas, ...
We present and discuss the photometric and spectroscopic evolution of the peculiar SN1998bw, associated with GRB980425, through an analysis of optical and near IR data collected at ESO-La Silla. The...
BeppoSAX confirmation of beamed afterglow emission from GRB990510 (2000)
Pian, Elena, Soffitta, Paolo, Alessi, Alessandro, Amati, Lorenzo, Costa, Enrico, Frontera, Filippo, ...
We compare the prompt X-ray (2-10 keV) emission of GRB990510 measured by the BeppoSAX Wide Field Cameras (WFC) during the burst to the X-ray afterglow detected by the BeppoSAX Narrow Field...
Tommasi, Leonardo, Diaz, Ruben, Palazzi, Eliana, Pian, Elena, Poretti, Ennio, Scaltriti, Franco, ...
The polarized and total flux of the BL Lac object PKS 2155-304 were monitored intensively and simultaneously in the optical UBVRI bands with the Turin photopolarimeter at the CASLEO 2.15 m telescope...
Discovery of the optical counterpart and early optical observations of GRB 990712 (2000)
Sahu, Kailash C., Vreeswijk, P. M., Bakos, Gaspar A., Menzies, John W., Bragaglia, Angela, Frontera, Filippo, ...
We present the discovery observations of the optical counterpart of the gamma-ray burst GRB 990712 taken 4.16 hr after the outburst and discuss its light curve observed in the V, R, and I bands...
Discovery of the optical counterpart and early optical observations of GRB 990712 (2000)
Sahu, Kailash C., Vreeswijk, P. M., Bakos, Gaspar A., Menzies, John W., Bragaglia, Angela, Frontera, Filippo, ...
We present the discovery observations of the optical counterpart of the gamma-ray burst GRB 990712 taken 4.16 hr after the outburst and discuss its light curve observed in the V, R, and I bands...
Fruchter, Andrew S., Thorsett, S. E., Metzger, Mark R., Sahu, Kailash C., Petro, Larry, Livio, Mario, ...
We report on HST and Palomar optical images of the field of GRB 990123, obtained on 8 and 9 February 1999. We find that the optical transient (OT) associated with GRB 990123 is located on an...
BeppoSAX Observations of the galactic source GS1826-238 in a hard X-ray high state (1999)
Del Sordo, Stefano, Frontera, Filippo, Pian, Elena, Piraino, Santina, Oosterbroek, Tim, Harmon, B. A., ...
The BeppoSAX Narrow Field Instruments observed the galactic source GS1826-238 in October 1997, following a hard X-ray outburst with a peak flux of about 100 mCrab detected by BATSE. Two short X-ray...
Falomo, Renato, Maraschi, Laura, Pian, Elena, Treves, Aldo
The contribution of an astrophysics group based in Milan to the science with the IUE satellite during its almost 20 years lifetime has focussed on high energy sources, of both galactic (LMXRB, HMXRB,...
Pian, Elena, Malaguti, Giuseppe, Maraschi, Laura, Ghisellini, Gabriele, Palumbo, Giorgio G. C.
Only ~10 blazars have been detected in soft gamma-rays by OSSE and the PDS, often in flaring state. We investigate the impact of the imaging and spectral capabilities of the IBIS instrument on board...
BeppoSAX Observations of the BL Lac Object Mkn 501 in an Intermediate State (1998)
Pian, Elena, Palazzi, Eliana, Chiappetti, Lucio, Maraschi, Laura, Tavecchio, Fabrizio, Ghisellini, Gabriele, ...
The BL Lac object Mkn 501 was observed with the BeppoSAX satellite at three epochs in April-May 1998, simultaneously with the Whipple and HEGRA Cherenkov telescopes. The X-ray spectrum is well...
HST/STIS Observations of the Optical Counterpart to GRB 970228 (1998)
Fruchter, Andrew S., Pian, Elena, Thorsett, Stephen E., Gonzalez, Rosa, Sahu, Kailash C., Mutchler, Max, ...
We report on observations of the fading optical counterpart of the gamma-ray burst GRB 970228, made on 4~September~1997 using the STIS CCD on the Hubble Space Telescope. The unresolved counterpart is...
The Gamma Ray Bursts GRB970228 and GRB970508: What Have We Learnt? (1997)
Livio, Mario, Sahu, Kailash C., Petro, Larry, Fruchter, Andrew, Pian, Elena, Macchetto, F. Duccio, ...
We examine what we regard as key observational results on GRB 970228 and GRB 970508 and show that the accumulated evidence strongly suggests that gamma-ray bursts (GRBs) are cosmological fireballs....
BeppoSAX Observations of Unprecedented Synchrotron Activity in the BL Lac Object Mkn 501 (1997)
Pian, Elena, Vacanti, Giuseppe, Tagliaferri, Gianpiero, Ghisellini, Gabriele, Maraschi, Laura, Treves, Aldo, ...
The BL Lac object Mkn 501, one of the only three extragalactic sources (with Mkn 421 and 1ES 2344+514) so far detected at TeV energies, was observed with the BeppoSAX satellite on 7, 11, and 16 April...
Hubble Space Telescope Imaging of the Optical Transient Associated with GRB970508 (1997)
Pian, Elena, Fruchter, Andrew S., Bergeron, Louis E., Thorsett, Steve E., Frontera, Filippo, Tavani, Marco, ...
We report on Hubble Space Telescope (HST) observations of the optical transient (OT) discovered in the error box of the gamma-ray burst GRB970508. The object was imaged on 1997 June 2 with the Space...
Monitoring Ly alpha Emission from the Blazar 3C 279 (1997)
Koratkar, Anuradha, Pian, Elena, Urry, C. Megan, Pesce, Joseph E.
The blazar 3C 279 is well studied and shows frequent large continuum flares from radio to gamma-ray wavelengths. There have been a number of multi-wavelength observations of 3C 279, and hence there...
Pian, Elena, Urry, C. Megan, Treves, Aldo, Maraschi, Laura, Penton, Steve, Shull, J. Michael, ...
PKS 2155-304, the brightest BL Lac object in the ultraviolet sky, was monitored with the IUE satellite at ~1 hour time-resolution for ten nearly uninterrupted days in May 1994. The campaign, which...