R. Desiante | Istituto Nazionale di Fisica Nucleare (original) (raw)

Papers by R. Desiante

Research paper thumbnail of Fermi-Lat Gamma-Ray Detections of Classical Novae V1369 Centauri 2013 and V5668 Sagittarii 2015

The Astrophysical Journal, 2016

Research paper thumbnail of Analysis of the Impulsive Phase of Solar Flares with Pass 8 LAT data

We show the results of analyses performed on high-energy gamma-ray emission during the impulsive ... more We show the results of analyses performed on high-energy gamma-ray emission during the impulsive phase of solar flares detected by the LAT using Pass 8 data. We compare results obtained with Pass 7 and Pass 8 data sets, using both LAT Low Energy and standard data classes. With a dedicated event selection, Pass 8 allows standard analysis during the impulsive phase: it has been designed to be less susceptible to pile-up in the LAT Anti-Coincidence Detector caused by the intense hard X-ray emission at early times.

Research paper thumbnail of Clustering of LAT light curves: a clue to the origin of high-energy emission in gamma-ray bursts

Monthly Notices of the Royal Astronomical Society, 2014

The physical origin of the > 0.1 GeV emission detected from Gamma-Ray Bursts (GRBs) by the Fermi ... more The physical origin of the > 0.1 GeV emission detected from Gamma-Ray Bursts (GRBs) by the Fermi satellite has not yet been completely understood. In this work we consider the GeV light curves of ten GRBs with measured redshift detected by the Fermi-LAT. These light curves are characterised by a long-lived ( 10 2 seconds) emission, whose luminosity decays in time as a power-law. While the decay rate is similar for all GRBs (i.e. L LAT ∝ t −1.2 ), the normalisation spans about two orders of magnitude in luminosity. However, after re-normalising the luminosities to the prompt energetics E prompt the light curves overlap. We consider the scenario in which the temporally extended LAT emission is dominated by synchrotron radiation from electrons accelerated at the forward external shock. According to this model, at high-energies (i.e. above the typical synchrotron frequencies) a small dispersion of the E promptnormalised light curves is expected. The fact that the LAT temporally extended emission follows this behaviour reinforces its interpretation in terms of afterglow radiation from external shocks. Assuming this scenario, we argue that the parameters ǫ e and η γ (i.e., the fraction of shock-dissipated energy gained by the electrons, and the efficiency of the mechanism producing the prompt radiation, respectively) must be narrowly distributed.

Research paper thumbnail of A hint to the origin of the extended emission in LAT GRBs: the relation between LAT luminosity and prompt energetics

We consider the 0.1-10 GeV rest frame light curves of 10 GRBs detected by LAT and with known reds... more We consider the 0.1-10 GeV rest frame light curves of 10 GRBs detected by LAT and with known redshift. In all cases the emission persists after the prompt has faded away. This extended emission decays in time as a power-law. The decay slope is similar among different bursts, while the normalization spans more than 2 decades. However, when the LAT luminosity is normalized to the 1 keV-10 MeV energetics of the prompt emission E_iso all light curves become consistent with having the same normalization, i.e. they cluster. At each given time the ratio between the LAT luminosity and the prompt energetics is narrowly distributed. We argue that this result is expected in the external shock scenario and it strengthens the interpretation of the GeV emission in terms of radiation from external shocks. In this context, we derive limits on the distribution of epsilon_e (the fraction of the shock energy that goes into electrons) and eta (the efficiency of the mechanism producing the prompt).

Research paper thumbnail of GRB 131029A: Fermi-LAT detection of a burst

Research paper thumbnail of Measurement of the high-energy gamma-ray emission from the Moon with the Fermi Large Area Telescope

Research paper thumbnail of The Firstfermilat Supernova Remnant Catalog

The Astrophysical Journal Supplement Series, 2016

Research paper thumbnail of Fermi-Lat Observations of the Ligo Event GW150914

The Astrophysical Journal, 2016

Research paper thumbnail of Fermilarge Area Telescope Detection of Extended Gamma-Ray Emission from the Radio Galaxy Fornax a

The Astrophysical Journal, 2016

Research paper thumbnail of MINUTE-TIMESCALE >100 MeVγ-RAY VARIABILITY DURING THE GIANT OUTBURST OF QUASAR 3C 279 OBSERVED BYFERMI-LAT IN 2015 JUNE

The Astrophysical Journal, 2016

Research paper thumbnail of Localization and Broadband Follow-Up of the Gravitational-Wave Transient GW150914

The Astrophysical Journal, 2016

A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interfe... more A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground-and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams.

Research paper thumbnail of SUPPLEMENT: “LOCALIZATION AND BROADBAND FOLLOW-UP OF THE GRAVITATIONAL-WAVE TRANSIENT GW150914” (2016, ApJL, 826, L13)

The Astrophysical Journal Supplement Series, 2016

Research paper thumbnail of FERMILAT STACKING ANALYSIS OFSWIFTLOCALIZED GRBs

The Astrophysical Journal, 2016

Research paper thumbnail of Development of the Model of Galactic Interstellar Emission for Standard Point-Source Analysis Offermilarge Area Telescope Data

The Astrophysical Journal Supplement Series, 2016

Research paper thumbnail of Resolving the Extragalactic γ-Ray Background above 50 GeV with the Fermi Large Area Telescope

Physical review letters, Jan 15, 2016

The Fermi Large Area Telescope (LAT) Collaboration has recently released a catalog of 360 sources... more The Fermi Large Area Telescope (LAT) Collaboration has recently released a catalog of 360 sources detected above 50 GeV (2FHL). This catalog was obtained using 80 months of data re-processed with Pass 8, the newest event-level analysis, which significantly improves the acceptance and angular resolution of the instrument. Most of the 2FHL sources at high Galactic latitude are blazars. Using detailed Monte Carlo simulations, we measure, for the first time, the source count distribution, dN/dS, of extragalactic γ-ray sources at E>50 GeV and find that it is compatible with a Euclidean distribution down to the lowest measured source flux in the 2FHL (∼8×10^{-12} ph cm^{-2} s^{-1}). We employ a one-point photon fluctuation analysis to constrain the behavior of dN/dS below the source detection threshold. Overall, the source count distribution is constrained over three decades in flux and found compatible with a broken power law with a break flux, S_{b}, in the range [8×10^{-12},1.5×10...

Research paper thumbnail of Search for Spectral Irregularities due to Photon–Axionlike-Particle Oscillations with the Fermi Large Area Telescope

Physical Review Letters, 2016

We report on the search for spectral irregularities induced by oscillations between photons and a... more We report on the search for spectral irregularities induced by oscillations between photons and axionlike-particles (ALPs) in the γ-ray spectrum of NGC 1275, the central galaxy of the Perseus cluster. Using 6 years of Fermi Large Area Telescope data, we find no evidence for ALPs and exclude couplings above 5×10^{-12} GeV^{-1} for ALP masses 0.5≲m_{a}≲5 neV at 95% confidence. The limits are competitive with the sensitivity of planned laboratory experiments, and, together with other bounds, strongly constrain the possibility that ALPs can reduce the γ-ray opacity of the Universe.

Research paper thumbnail of Deep Morphological and Spectral Study of the SNR RCW 86 with Fermi -Lat

The Astrophysical Journal, 2016

Research paper thumbnail of Fermi -Lat Observations of High-Energy Γ -Ray Emission Toward the Galactic Center

The Astrophysical Journal, 2016

Research paper thumbnail of Search for Gamma-Ray Emission from the Coma Cluster with Six Years Offermi-Lat Data

The Astrophysical Journal, 2016

Research paper thumbnail of Contemporaneous Broadband Observations of Three High-Redshift BL Lac Objects

The Astrophysical Journal, 2016

Research paper thumbnail of Fermi-Lat Gamma-Ray Detections of Classical Novae V1369 Centauri 2013 and V5668 Sagittarii 2015

The Astrophysical Journal, 2016

Research paper thumbnail of Analysis of the Impulsive Phase of Solar Flares with Pass 8 LAT data

We show the results of analyses performed on high-energy gamma-ray emission during the impulsive ... more We show the results of analyses performed on high-energy gamma-ray emission during the impulsive phase of solar flares detected by the LAT using Pass 8 data. We compare results obtained with Pass 7 and Pass 8 data sets, using both LAT Low Energy and standard data classes. With a dedicated event selection, Pass 8 allows standard analysis during the impulsive phase: it has been designed to be less susceptible to pile-up in the LAT Anti-Coincidence Detector caused by the intense hard X-ray emission at early times.

Research paper thumbnail of Clustering of LAT light curves: a clue to the origin of high-energy emission in gamma-ray bursts

Monthly Notices of the Royal Astronomical Society, 2014

The physical origin of the > 0.1 GeV emission detected from Gamma-Ray Bursts (GRBs) by the Fermi ... more The physical origin of the > 0.1 GeV emission detected from Gamma-Ray Bursts (GRBs) by the Fermi satellite has not yet been completely understood. In this work we consider the GeV light curves of ten GRBs with measured redshift detected by the Fermi-LAT. These light curves are characterised by a long-lived ( 10 2 seconds) emission, whose luminosity decays in time as a power-law. While the decay rate is similar for all GRBs (i.e. L LAT ∝ t −1.2 ), the normalisation spans about two orders of magnitude in luminosity. However, after re-normalising the luminosities to the prompt energetics E prompt the light curves overlap. We consider the scenario in which the temporally extended LAT emission is dominated by synchrotron radiation from electrons accelerated at the forward external shock. According to this model, at high-energies (i.e. above the typical synchrotron frequencies) a small dispersion of the E promptnormalised light curves is expected. The fact that the LAT temporally extended emission follows this behaviour reinforces its interpretation in terms of afterglow radiation from external shocks. Assuming this scenario, we argue that the parameters ǫ e and η γ (i.e., the fraction of shock-dissipated energy gained by the electrons, and the efficiency of the mechanism producing the prompt radiation, respectively) must be narrowly distributed.

Research paper thumbnail of A hint to the origin of the extended emission in LAT GRBs: the relation between LAT luminosity and prompt energetics

We consider the 0.1-10 GeV rest frame light curves of 10 GRBs detected by LAT and with known reds... more We consider the 0.1-10 GeV rest frame light curves of 10 GRBs detected by LAT and with known redshift. In all cases the emission persists after the prompt has faded away. This extended emission decays in time as a power-law. The decay slope is similar among different bursts, while the normalization spans more than 2 decades. However, when the LAT luminosity is normalized to the 1 keV-10 MeV energetics of the prompt emission E_iso all light curves become consistent with having the same normalization, i.e. they cluster. At each given time the ratio between the LAT luminosity and the prompt energetics is narrowly distributed. We argue that this result is expected in the external shock scenario and it strengthens the interpretation of the GeV emission in terms of radiation from external shocks. In this context, we derive limits on the distribution of epsilon_e (the fraction of the shock energy that goes into electrons) and eta (the efficiency of the mechanism producing the prompt).

Research paper thumbnail of GRB 131029A: Fermi-LAT detection of a burst

Research paper thumbnail of Measurement of the high-energy gamma-ray emission from the Moon with the Fermi Large Area Telescope

Research paper thumbnail of The Firstfermilat Supernova Remnant Catalog

The Astrophysical Journal Supplement Series, 2016

Research paper thumbnail of Fermi-Lat Observations of the Ligo Event GW150914

The Astrophysical Journal, 2016

Research paper thumbnail of Fermilarge Area Telescope Detection of Extended Gamma-Ray Emission from the Radio Galaxy Fornax a

The Astrophysical Journal, 2016

Research paper thumbnail of MINUTE-TIMESCALE >100 MeVγ-RAY VARIABILITY DURING THE GIANT OUTBURST OF QUASAR 3C 279 OBSERVED BYFERMI-LAT IN 2015 JUNE

The Astrophysical Journal, 2016

Research paper thumbnail of Localization and Broadband Follow-Up of the Gravitational-Wave Transient GW150914

The Astrophysical Journal, 2016

A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interfe... more A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground-and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams.

Research paper thumbnail of SUPPLEMENT: “LOCALIZATION AND BROADBAND FOLLOW-UP OF THE GRAVITATIONAL-WAVE TRANSIENT GW150914” (2016, ApJL, 826, L13)

The Astrophysical Journal Supplement Series, 2016

Research paper thumbnail of FERMILAT STACKING ANALYSIS OFSWIFTLOCALIZED GRBs

The Astrophysical Journal, 2016

Research paper thumbnail of Development of the Model of Galactic Interstellar Emission for Standard Point-Source Analysis Offermilarge Area Telescope Data

The Astrophysical Journal Supplement Series, 2016

Research paper thumbnail of Resolving the Extragalactic γ-Ray Background above 50 GeV with the Fermi Large Area Telescope

Physical review letters, Jan 15, 2016

The Fermi Large Area Telescope (LAT) Collaboration has recently released a catalog of 360 sources... more The Fermi Large Area Telescope (LAT) Collaboration has recently released a catalog of 360 sources detected above 50 GeV (2FHL). This catalog was obtained using 80 months of data re-processed with Pass 8, the newest event-level analysis, which significantly improves the acceptance and angular resolution of the instrument. Most of the 2FHL sources at high Galactic latitude are blazars. Using detailed Monte Carlo simulations, we measure, for the first time, the source count distribution, dN/dS, of extragalactic γ-ray sources at E>50 GeV and find that it is compatible with a Euclidean distribution down to the lowest measured source flux in the 2FHL (∼8×10^{-12} ph cm^{-2} s^{-1}). We employ a one-point photon fluctuation analysis to constrain the behavior of dN/dS below the source detection threshold. Overall, the source count distribution is constrained over three decades in flux and found compatible with a broken power law with a break flux, S_{b}, in the range [8×10^{-12},1.5×10...

Research paper thumbnail of Search for Spectral Irregularities due to Photon–Axionlike-Particle Oscillations with the Fermi Large Area Telescope

Physical Review Letters, 2016

We report on the search for spectral irregularities induced by oscillations between photons and a... more We report on the search for spectral irregularities induced by oscillations between photons and axionlike-particles (ALPs) in the γ-ray spectrum of NGC 1275, the central galaxy of the Perseus cluster. Using 6 years of Fermi Large Area Telescope data, we find no evidence for ALPs and exclude couplings above 5×10^{-12} GeV^{-1} for ALP masses 0.5≲m_{a}≲5 neV at 95% confidence. The limits are competitive with the sensitivity of planned laboratory experiments, and, together with other bounds, strongly constrain the possibility that ALPs can reduce the γ-ray opacity of the Universe.

Research paper thumbnail of Deep Morphological and Spectral Study of the SNR RCW 86 with Fermi -Lat

The Astrophysical Journal, 2016

Research paper thumbnail of Fermi -Lat Observations of High-Energy Γ -Ray Emission Toward the Galactic Center

The Astrophysical Journal, 2016

Research paper thumbnail of Search for Gamma-Ray Emission from the Coma Cluster with Six Years Offermi-Lat Data

The Astrophysical Journal, 2016

Research paper thumbnail of Contemporaneous Broadband Observations of Three High-Redshift BL Lac Objects

The Astrophysical Journal, 2016