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48 results on '"La Mura, Giovanni"'

1. A large jet narrow-line Seyfert 1 galaxy: observations from pc to 100 kpc scales

Author

Chen, Sina, Kharb, Preeti, Sasikumar, Silpa, Nandi, Sumana, Berton, Marco, Jarvela, Emilia, Laor, Ari, Behar, Ehud, Foschini, Luigi, Vietri, Amelia, Gu, Minfeng, La Mura, Giovanni, Crepaldi, Luca, and Zhou, Minhua

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present new 1.5-8.5 GHz Very Long Baseline Array (VLBA) observations and 0.32-1.26 GHz Giant Meterwave Radio Telescope (GMRT) observations of J0354-1340, which is the only known radio-quiet (RQ) or radio-intermediate (RI) narrow-line Seyfert 1 galaxy with a 100-kpc two-sided radio jet. A pc-scale one-sided jet in the southeast direction from the core emission is found in the VLBA observations, while the kpc-scale jet observed with Karl G. Jansky Very Large Array (VLA) and GMRT is in the south-north direction. The core spectra on pc and kpc scales are presented in combination with the archival VLASS observations at 3.0 GHz and the VLA C configuration observations at 5.5 GHz. The pc-scale emission dominates the kpc-scale emission above ~ 5 GHz, and the spectrum is inverted due to synchrotron self-absorption. This indicates a compact synchrotron source with a size of ~ 0.04 pc, which is associated with either the jet base or the corona. A sub-kpc scale jet, which is unresolved on scales of ~ 3 arcsec, probably dominates the emission below ~ 5 GHz. Future radio observations can explore the jet structure between the pc and 100 kpc scales, the origin of their direction mismatch, and the pc-scale jet proper motion. It remains to be explored how common such large-scale jets are in RQ or RI AGN., Comment: Accepted for publication in ApJ

Published
2023

2. Optical properties of two complementary samples of intermediate Seyfert galaxies

Author

Barba, Benedetta Dalla, Berton, Marco, Foschini, Luigi, La Mura, Giovanni, Vietri, Amelia, and Ciroi, Stefano

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present preliminary results of the analysis of optical spectra of two complementary samples of Seyfert galaxies. The first sample was extracted from a selection of the 4th Fermi Gamma-ray Large Area Telescope (4FGL) catalog, and consists of 9 $\gamma$-ray emitting jetted Seyfert galaxies. The second one was extracted from the Swift-BAT AGN Spectroscopic Survey (BASS), and is composed of 38 hard-X ray selected Active Galactic Nuclei (AGN). These two samples are complementary, with the former expected to have smaller viewing angles, while the latter may include objects with larger viewing angles. We measured emission line ratios to investigate whether the behavior of these Seyferts can be explained in terms of obscuration, as suggested by the well-known Unified Model (UM) of AGN, or if there are intrinsic differences due to the presence of jets, outflows, or the evolution. We found no indications of intrinsic differences. The UM remains the most plausible interpretation for these classes of objects even if some results can be challenging for this model., Comment: 24 pages, 10 figures, conference proceeding "14th Serbian Conference on Spectral Line Shapes in Astrophysics"

Published
2023

3. Long-term monitoring of the broad-line region properties in a selected sample of AGN

Author

Ilic, Dragana, Shapovalova, Alla I., Popovic, Luka C., Chavushyan, Vahram, Burenkov, Alexander N., Kollatschny, Wolfram, Kovacevic, Andjelka, Marceta-Mandic, Sladjana, Rakic, Nemanja, La Mura, Giovanni, and Rafanelli, Piero

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the results of the long-term optical monitoring campaign of active galactic nuclei (AGN) coordinated by the Special Astrophysical Observatory of the Russian Academy of Science. This campaign has produced a remarkable set of optical spectra, since we have monitored for several decades different types of broad-line (type 1) AGN, from a Seyfert 1, double-peaked line, radio loud and radio quiet AGN, to a supermassive binary black hole candidate. Our analysis of the properties of the broad line region (BLR) of these objects is based on the variability of the broad emission lines. We hereby give a comparative review of the variability properties of the broad emission lines and the BLR of seven different type 1 AGNs, emphasizing some important results, such as the variability rate, the BLR geometry, and the presence of the intrinsic Baldwin effect. We are discussing the difference and similarity in the continuum and emission line variability, focusing on what is the impact of our results to the supermassive black hole mass determination from the BLR properties., Comment: Published in Frontiers in Astronomy and Space Science

Published
2018
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4. Models of emission line profiles and spectral energy distributions to characterize the multi-frequency properties of active galactic nuclei

Author

La Mura, Giovanni, Berton, Marco, Chen, Sina, Chougule, Abhishek, Ciroi, Stefano, Congiu, Enrico, Cracco, Valentina, Frezzato, Michele, Mordini, Sabrina, and Rafanelli, Piero

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

The spectra of Active Galactic Nuclei (AGNs) are often characterized by a wealth of emission lines with different profiles and intensity ratios that led to a complicated classification. Their electro-magnetic radiation spans more than 10 orders of magnitude in frequency. In spite of the differences between various classes, the origin of their activity is attributed to a combination of emitting components, surrounding an accreting Super Massive Black Hole, in the so called Unified Model. Currently, the execution of sky surveys, with instruments operating at various frequencies, provides the possibility to detect and to investigate the properties of AGNs on very large statistical samples. Thanks to the spectroscopic surveys that allow investigation of many objects, we have the opportunity to place new constraints on the nature and evolution of AGNs. In this contribution we present the results obtained by working on multi-frequency data and we discuss their relations with the available optical spectra. We compare our findings with the AGN Unified Model predictions, and we present a revised technique to select AGNs of different types from other line emitting objects. We discuss the multi-frequency properties in terms of the innermost structures of the sources., Comment: 11 pages, 4 figures. Proceedings of the XI Serbian Conference on Spectral Line Shapes in Astrophysics. Accepted for publication on Atoms

Published
2017

5. Multi-frequency databases for AGN investigation - Results and perspectives

Author

La Mura, Giovanni, Berton, Marco, Chen, Sina, Ciroi, Stefano, Congiu, Enrico, Cracco, Valentina, Frezzato, Michele, and Rafanelli, Piero

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

Active Galactic Nuclei (AGNs) are characterized by emission of radiation over more than 10 orders of magnitude in frequency. Therefore, the execution of extensive surveys of the sky, with different types of detectors, is providing the attractive possibility to identify and to investigate the properties of AGNs on very large statistical samples. Thanks to the large spectroscopic surveys that allow detailed investigation of many of these sources, we have the opportunity to place new constraints on the nature and evolution of AGNs and to investigate their relations with the host systems. In this contribution we present the results that can be obtained by using a new interactive catalogue that we developed to investigate the range of AGN spectral energy distributions (SEDs). We present simple SED models based on data collected in the catalogue and discuss their relations with optical spectra obtained by follow up observations. We compare our findings with the expectations based on the AGN Unification Model, and we discuss the perspectives of multi-wavelength approaches to address AGN related processes such as black hole accretion and acceleration of relativistic jets., Comment: 11 pages, 2 color figures, proceedings of the conference "QUASARS at all cosmic epochs", accepted for publication on Frontiers in Astronomy and Space Science

Published
2017

6. Extended narrow-line region in Seyfert galaxies

Author

Congiu, Enrico, Contini, Marcella, Ciroi, Stefano, Cracco, Valentina, Di Mille, Francesco, Berton, Marco, Frezzato, Michele, La Mura, Giovanni, and Rafanelli, Piero

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present our recent results about the extended narrow-line region (ENLR) of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212) obtained by modelling the observed line profiles and spectra with composite models (photoionization+shocks) in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as a) the contribution of shocks in ionizing the high velocity gas, b) the complex kinematics showed by the profile of the emission lines, c) the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas., Comment: 9 pages, 2 figures, proceeding of the conference "Quasars at all cosmic epochs", accepted for publication in Front. Astron. Space Sci. - Milky Way and Galaxies

Published
2017

7. 3FGLzoo. Classifying 3FGL Unassociated Fermi-LAT Gamma-ray Sources by Artificial Neural Networks

Author

Salvetti, David, Chiaro, Graziano, La Mura, Giovanni, and Thompson, David J.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

In its first four years of operation, the Fermi Large Area Telescope (LAT) detected 3033 $\gamma$-ray emitting sources. In the Fermi-LAT Third Source Catalogue (3FGL) about 50% of the sources have no clear association with a likely $\gamma$-ray emitter. We use an artificial neural network algorithm aimed at distinguishing BL Lacs from FSRQs to investigate the source subclass of 559 3FGL unassociated sources characterised by $\gamma$-ray properties very similar to those of Active Galactic Nuclei. Based on our method, we can classify 271 objects as BL Lac candidates, 185 as FSRQ candidates, leaving only 103 without a clear classification. we suggest a new zoo for $\gamma$-ray objects, where the percentage of sources of uncertain type drops from 52% to less than 10%. The result of this study opens up new considerations on the population of the $\gamma$-ray sky, and it will facilitate the planning of significant samples for rigorous analyses and multiwavelength observational campaigns., Comment: 8 pages, 4 figures, 3 tables, accepted for publication in MNRAS

Published
2017
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8. The intrinsic Baldwin effect in broad Balmer lines of six long-term monitored AGNs

Author

Rakic, Nemanja, La Mura, Giovanni, Ilic, Dragana, Shapovalova, Alla I., Kollatschny, Wolfram, Rafanelli, Piero, and Popovic, Luka C.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We investigate the intrinsic Baldwin effect (Beff) of the broad H$\alpha$ and H$\beta$ emission lines for six Type 1 active galactic nuclei (AGNs) with different broad line characteristics: two Seyfert 1 (NGC 4151 and NGC 5548), two AGNs with double-peaked broad line profiles (3C 390.3 and Arp 102B), one narrow line Seyfert 1 (Ark 564), and one high-luminosity quasar with highly red asymmetric broad line profiles (E1821+643). We found that a significant intrinsic Beff was present in all Type 1 AGNs in our sample. Moreover, we do not see strong difference in intrinsic Beff slopes in different types of AGNs which probably have different physical properties, such as inclination, broad line region geometry, or accretion rate. Additionally, we found that the intrinsic Beff was not connected with the global one, which, instead, could not be detected in the broad H$\alpha$ or H$\beta$ emission lines. In the case of NGC 4151, the detected variation of the Beff slope could be due to the change in the site of line formation in the BLR. Finally, the intrinsic Beff might be caused by the additional optical continuum component that is not part of the ionization continuum., Comment: 12 pages, 8 figures, Accepted for publication in A&A

Published
2017
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9. Relativistic plasmas in AGN jets - From synchrotron radiation to $\gamma$-ray emission

Author

La Mura, Giovanni, Busetto, Giovanni, Ciroi, Stefano, Rafanelli, Piero, Berton, Marco, Congiu, Enrico, Cracco, Valentina, and Frezzato, Michele

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Relativistic jets of plasma are a key ingredient of many types of Active Galactic Nuclei (AGN). Today we know that AGNs are powered by the accretion of inter stellar material into the gravitational field of a Super Massive Black Hole and that this process can release as much power as a whole galaxy, like the Milky Way, from a region that is comparable to the Solar System in size. Depending on the properties of the central energy source, a large fraction of this power can be involved in the acceleration of magnetized plasmas at relativistic speeds, to form large scale jets. The presence of jets affects the spectrum of AGNs through the emission of synchrotron radiation and Inverse Compton scattering of low energy photons, thus leading to a prominent non-thermal spectrum, some times extending from radio frequencies all the way up to $\gamma$-ray energies. Here we review some characteristic processes of radiation emission in AGN jets, which lead to the emission of photons in the radio, optical, X-ray and $\gamma$-ray bands, and we present the results of a spectroscopic campaign of optical counterparts. We discuss our observations and their connection with $\gamma$-ray properties in a scenario that traces the role of relativistic jets in different classes of AGNs, detected both in the local as well as in the remote Universe., Comment: 11 pages, 5 figures (3 in color), proceedings of the XXVIII School on Physics of Ionized Gases (SPIG), accepted for publication on the European Journal of Physics D

Published
2017
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10. Compact steep-spectrum sources as the parent population of flat-spectrum radio-loud NLS1s

Author

Berton, Marco, Caccianiga, Alessandro, Foschini, Luigi, Peterson, Bradley M., Mathur, Smita, Terreran, Giacomo, Ciroi, Stefano, Congiu, Enrico, Cracco, Valentina, Frezzato, Michele, La Mura, Giovanni, and Rafanelli, Piero

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

Narrow-line Seyfert 1 galaxies (NLS1s) are an interesting subclass of active galactic nuclei (AGN), which tipically does not exhibit any strong radio emission. Seven percent of them, though, are radio-loud and often show a flat radio-spectrum (F-NLS1s). This, along to the detection of $\gamma$-ray emission coming from them, is usually interpreted as a sign of a relativistic beamed jet oriented along the line of sight. An important aspect of these AGN that must be understood is the nature of their parent population, in other words how do they appear when observed under different angles. In the recent literature it has been proposed that a specific class of radio-galaxies, compact-steep sources (CSS) classified as high excitation radio galaxies (HERG), can represent the parent population of F-NLS1s. To test this hypothesis in a quantitative way,in this paper we analyzed the only two statistically complete samples of CSS/HERGs and F-NLS1s available in the literature. We derived the black hole mass and Eddington ratio distributions, and we built for the first time the radio luminosity function of F-NLS1s. Finally, we applied a relativistic beaming model to the luminosity function of CSS/HERGs, and compared the result with the observed function of F-NLS1s. We found that compact steep-spectrum sources are valid parent candidates and that F-NLS1s, when observed with a different inclination, might actually appear as CSS/HERGs., Comment: 9 pages, 5 figures, 4 tables. Accepted for publication in Astronomy & Astrophysics

Published
2016
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12. Parent population of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

Author

Berton, Marco, Foschini, Luigi, Ciroi, Stefano, Cracco, Valentina, La Mura, Giovanni, Lister, Matthew L., Mathur, Smita, Peterson, Bradley M., Richards, Joseph L., and Rafanelli, Piero

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

Flat-spectrum radio-loud Narrow-Line Seyfert 1 galaxies (NLS1s) are a recently discovered class of $\gamma$-ray emitting Active Galactic Nuclei (AGN), that exhibit some blazar-like properties which are explained with the presence of a relativistic jet viewed at small angles. When blazars are observed at larger angles they appear as radio-galaxies, and we expect to observe an analogue parent population for beamed NLS1s. However, the number of known NLS1s with the jet viewed at large angles is not enough. Therefore, we tried to understand the origin of this deficit. Current hypotheses about the nature of parent sources are steep-spectrum radio-loud NLS1s, radio-quiet NLS1s and disk-hosted radio-galaxies. To test these hypotheses we built three samples of candidate sources plus a control sample, and calculated their black hole mass and Eddington ratio using their optical spectra. We then performed a Kolmogorov-Smirnov statistical test to investigate the compatibility of our different samples with a beamed population. Our results indicate that, when the inclination angle increases, a beamed source appears as a steep-spectrum radio-loud NLS1, or possibly even as a disk-hosted radio-galaxy with low black hole mass and high Eddington ratio. Further investigations, involving larger complete samples and observations at radio frequency, are needed to understand the incidence of disk-hosted radio-galaxies in the parent population, and to assess whether radio-quiet NLS1s can play a role, as well., Comment: 12 pages, 6 figures, accepted for publication by Astronomy and Astrophysics

Published
2015
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14. Very high energy sky monitoring with the Southern Widefield Gamma-ray Observatory

Author

La Mura Giovanni, Barres de Almeida Ulisses, and Longo Francesco

Subjects
Physics, QC1-999
Abstract

The Southern Wide-field Gamma-ray Observatory (SWGO) is the proposal for a new ground-based γ-ray instrument in the Southern Hemisphere, which will use an array of water-Cherenkov particle detectors to provide continuous monitoring of a large portion of the sky at the very- and ultra-high-energies (VHE and UHE, respectively). At the low energy side, SWGO aims to push the observational range of wide-field ground-based γ-ray facilities down to a few hundred GeV, thus bridging the gap between space and ground-based facilities in the monitoring of the VHE sky. In the high energy domain, on the contrary, it will benefit from the optimal coverage of the Galactic Plane to map the distribution of UHE sources in the inner parts of the Galactic disk and close to the Galactic Center, leading to an extraordinary improvement in our ability to identify their most likely counterparts. In this contribution, we describe the concept of SWGO and its potential to constrain the physics of VHE emission and particle acceleration in γ-ray sources powered by relativistic jets and energetic shocks. We finally discuss its role within the global network of multi-messenger facilities.

Published
2023
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19. Gamma/hadron discrimination using a small-WCD with four PMTs

Author

Conceição, Rúben, primary, Assis, Pedro, additional, Assunção, Filipe, additional, Bakalova, Alena, additional, Barres de Almeida, Ulisses, additional, Roque Bom, Clécio, additional, Correia, João, additional, De Angelis, Alessandro, additional, Dias, Luciana Olivia, additional, Serrano González, Borja, additional, Guillén, Alberto, additional, La Mura, Giovanni, additional, Lourenço, Nuno, additional, Machado, Penousal, additional, Marques, Sara, additional, Mendes, Luis, additional, Pimenta, Mário, additional, Shellard, Ronald, additional, Tomé, Bernardo, additional, and Vicha, Jakub, additional

Published
2021
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21. The Sub-TeV transient Gamma-Ray sky: challenges and opportunities

Author

La Mura, Giovanni, primary, Assis, Pedro, additional, Blanco, Alberto, additional, Conceição, Rúben, additional, Fonte, Paulo, additional, LOPES, Luis, additional, Pimenta, Mário, additional, Tomé, Bernardo, additional, Espírito Santo, Catarina, additional, Mendes, Luis, additional, Ferreira, Miguel, additional, Abreu, Pedro, additional, Brogueira, Pedro, additional, Barão, Fernando, additional, Barres de Almeida, Ulisses, additional, Shellard, Ronald, additional, GIACCARI, Ugo, additional, Lippmann, Otto, additional, D’Ettorre Piazzoli, Benedetto, additional, Doro, Michele, additional, Prandini, Elisa, additional, Perennes, Cédric, additional, Matthiae, Giorgio, additional, Tavani, Marco, additional, Santonico, Rinaldo, additional, De Angelis, Alessandro, additional, López Coto, Rubén, additional, Chiavassa, Andrea, additional, Vicha, Jakub, additional, Travnicek, Petr, additional, and Di Sciascio, Giuseppe, additional

Published
2020
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22. Einstein@Home discovers a radio-quiet gamma-ray millisecond pulsar

Author

Clark, Colin J., Pletsch, Holger J., Aulbert, Carsten, Orienti, Monica, Orlando, Elena, Palatiello, Michele, Paliya, Vaidehi S., de Palma, Francesco, Paneque, David, Perkins, Jeremy S., Persic, Massimo, Pesce-Rollins, Melissa, Porter, Troy A., Beer, Christian, Principe, Giacomo, Rainò, Silvia, Rando, Riccardo, Ray, Paul S., Razzano, Massimiliano, Reimer, Anita, Reimer, Olaf, Romani, Roger W., Saz Parkinson, Pablo M., Sgrò, Carmelo, Bock, Oliver, Siskind, Eric J., Smith, David A., Spada, Francesca, Spandre, Gloria, Spinelli, Paolo, Thayer, Jana B., Thompson, David J., Torres, Diego F., Troja, Eleonora, Vianello, Giacomo, Cuéllar, Andres, Wood, Kent, Wood, Matthew, Fermi-LAT Collaboration, Eggenstein, Heinz-Bernd, Fehrmann, Henning, Kramer, Michael, Kwang, Shawn A., Machenschalk, Bernd, Nieder, Lars, Wu, Jason, Ackermann, Markus, Ajello, Marco, Baldini, Luca, Ballet, Jean, Barbiellini, Guido, Bastieri, Denis, Bellazzini, Ronaldo, Bissaldi, Elisabetta, Blandford, Roger D., Bloom, Elliott D., Guillemot, Lucas, Bonino, Raffaella, Bottacini, Eugenio, Brandt, Terri J., Bregeon, Johan, Bruel, Philippe, Buehler, Rolf, Burnett, Toby H., Buson, Sara, Cameron, Rob A., Caputo, Regina, Kerr, Matthew, Caraveo, Patrizia A., Cavazzuti, Elisabetta, Cecchi, Claudia, Charles, Eric, Chekhtman, Alexandre, Ciprini, Stefano, Cominsky, Lynn R., Costantin, Denise, Cutini, Sara, D'Ammando, Filippo, Johnson, Tyrel J., De Luca, Andrea, Desiante, Rachele, Di Venere, Leonardo, Di Mauro, Mattia, Di Lalla, Niccolò, Digel, Seth W., Favuzzi, Cecilia, Ferrara, Elizabeth C., Franckowiak, Anna, Fukazawa, Yasushi, Camilo, Fernando, Funk, Stefan, Fusco, Piergiorgio, Gargano, Fabio, Gasparrini, Dario, Giglietto, Nico, Giordano, Francesco, Giroletti, Marcello, Gomez-Vargas, Germán A., Green, David, Grenier, Isabelle A., Salvetti, David, Guiriec, Sylvain, Harding, Alice K., Hewitt, John W., Horan, Deirdre, Jóhannesson, Guðlaugur, Kensei, Shiki, Kuss, Michael, La Mura, Giovanni, Larsson, Stefan, Latronico, Luca, Allen, Bruce, Li, Jian, Longo, Francesco, Loparco, Francesco, Lovellette, Michael N., Lubrano, Pasquale, Magill, Jeffrey D., Maldera, Simone, Manfreda, Alberto, Mazziotta, Mario N., McEnery, Julie E., Anderson, David, Michelson, Peter F., Mirabal, Nestor, Mitthumsiri, Warit, Mizuno, Tsunefumi, Monzani, Maria Elena, Morselli, Aldo, Moskalenko, Igor V., Nuss, Eric, Ohsugi, Takashi, Omodei, Nicola, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National d’Études Spatiales [Paris] (CNES), Unité Scientifique de la Station de Nançay (USN), Université d'Orléans (UO)-Observatoire des Sciences de l'Univers en région Centre (OSUC), PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Fermi-LAT, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), ITA, Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace ( LPC2E ), Centre National de la Recherche Scientifique ( CNRS ) -Université d'Orléans ( UO ) -Institut national des sciences de l'Univers ( INSU - CNRS ), Unité Scientifique de la Station de Nançay ( USN ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université d'Orléans ( UO ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire AIM, Université Paris Diderot - Paris 7 ( UPD7 ) -Centre d'Etudes de Saclay, Laboratoire Univers et Particules de Montpellier ( LUPM ), Centre National de la Recherche Scientifique ( CNRS ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Université Montpellier 2 - Sciences et Techniques ( UM2 ) -Université de Montpellier ( UM ), Laboratoire Leprince-Ringuet ( LLR ), Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -École polytechnique ( X ) -Centre National de la Recherche Scientifique ( CNRS ), Centre d'Etudes Nucléaires de Bordeaux Gradignan ( CENBG ), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Raunvísindastofnun (HÍ), Science Institute (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland, Clark, Colin J., Pletsch, Holger J., Wu, Jason, Guillemot, Luca, Kerr, Matthew, Johnson, Tyrel J., Camilo, Fernando, Salvetti, David, Allen, Bruce, Anderson, David, Aulbert, Carsten, Beer, Christian, Bock, Oliver, Cuéllar, Andre, Eggenstein, Heinz-Bernd, Fehrmann, Henning, Kramer, Michael, Kwang, Shawn A., Machenschalk, Bernd, Nieder, Lar, Ackermann, Marku, Ajello, Marco, Baldini, Luca, Ballet, Jean, Barbiellini, Guido, Bastieri, Deni, Bellazzini, Ronaldo, Bissaldi, Elisabetta, Blandford, Roger D., Bloom, Elliott D., Bonino, Raffaella, Bottacini, Eugenio, Brandt, Terri J., Bregeon, Johan, Bruel, Philippe, Buehler, Rolf, Burnett, Toby H., Buson, Sara, Cameron, Rob A., Caputo, Regina, Caraveo, Patrizia A., Cavazzuti, Elisabetta, Cecchi, Claudia, Charles, Eric, Chekhtman, Alexandre, Ciprini, Stefano, Cominsky, Lynn R., Costantin, Denise, Cutini, Sara, D'Ammando, Filippo, De Luca, Andrea, Desiante, Rachele, Di Venere, Leonardo, Di Mauro, Mattia, Di Lalla, Niccolò, Digel, Seth W., Favuzzi, Cecilia, Ferrara, Elizabeth C., Franckowiak, Anna, Fukazawa, Yasushi, Funk, Stefan, Fusco, Piergiorgio, Gargano, Fabio, Gasparrini, Dario, Giglietto, Nico, Giordano, Francesco, Giroletti, Marcello, Gomez-Vargas, Germán A., Green, David, Grenier, Isabelle A., Guiriec, Sylvain, Harding, Alice K., Hewitt, John W., Horan, Deirdre, Jóhannesson, Guolaugur, Kensei, Shiki, Kuss, Michael, La Mura, Giovanni, Larsson, Stefan, Latronico, Luca, Li, Jian, Longo, Francesco, Loparco, Francesco, Lovellette, Michael N., Lubrano, Pasquale, Magill, Jeffrey D., Maldera, Simone, Manfreda, Alberto, Mazziotta, Mario N., Mcenery, Julie E., Michelson, Peter F., Mirabal, Nestor, Mitthumsiri, Warit, Mizuno, Tsunefumi, Monzani, Maria Elena, Morselli, Aldo, Moskalenko, Igor V., Nuss, Eric, Ohsugi, Takashi, Omodei, Nicola, Orienti, Monica, Orlando, Elena, Palatiello, Michele, Paliya, Vaidehi S., De Palma, Francesco, Paneque, David, Perkins, Jeremy S., Persic, Massimo, Pesce-Rollins, Melissa, Porter, Troy A., Principe, Giacomo, Rainò, Silvia, Rando, Riccardo, Ray, Paul S., Razzano, Massimiliano, Reimer, Anita, Reimer, Olaf, Romani, Roger W., Parkinson, Pablo M. Saz, Sgrò, Carmelo, Siskind, Eric J., Smith, David A., Spada, Francesca, Spandre, Gloria, Spinelli, Paolo, Thayer, Jana B., Thompson, David J., Torres, Diego F., Troja, Eleonora, Vianello, Giacomo, Wood, Kent, and Wood, Matthew

Subjects
Einstein@Home, Gammageislar, [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], Astronomy, Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, law.invention, Telescope, Computer Science::Hardware Architecture, Bulge, Millisecond pulsar, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, education, 010303 astronomy & astrophysics, Research Articles, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), education.field_of_study, Line-of-sight, Multidisciplinary, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Nifteindastjörnur, Astrophysics::Instrumentation and Methods for Astrophysics, SciAdv r-articles, Computer Science::Computers and Society, Stjörnusjónaukar, Neutron star, ddc:500, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Fermi Gamma-ray Space Telescope, Research Article
Abstract

Millisecond pulsars (MSPs) are old neutron stars that spin hundreds of times per second and appear to pulsate as their emission beams cross our line of sight. To date, radio pulsations have been detected from all rotation-powered MSPs. In an attempt to discover radio-quiet gamma-ray MSPs, we used the aggregated power from the computers of tens of thousands of volunteers participating in the Einstein@Home distributed computing project to search for pulsations from unidentified gamma-ray sources in Fermi Large Area Telescope data. This survey discovered two isolated MSPs, one of which is the only known rotation-powered MSP to remain undetected in radio observations. These gamma-ray MSPs were discovered in completely blind searches without prior constraints from other observations, raising hopes for detecting MSPs from a predicted Galactic bulge population., This work was supported by the Max-Planck-Gesellschaft, the Deutsche Forschungsgemeinschaft through an Emmy Noether Research Grant [no. PL 710/1-1 (H.J.P.)], and NSF award 1104902. C.J.C. acknowledges support from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 715051; Spiders). W.M. was partially supported by the Thailand Research Fund (grants TRG5880173 and RTA5980003). M.R. was funded by the Italian Ministry of Education, University and Research (contract no. FIRB-2012-RBFR12PM1F). Work at the Naval Research Laboratory is supported by NASA. The Parkes Observatory is part of the Australia Telescope, funded by the Commonwealth of Australia for operation as a National Facility managed by the Commonwealth Scientific and Industrial Research Organisation (CSIRO). The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT, as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France; the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK), and Japan Aerospace Exploration Agency (JAXA) in Japan; and the K. A. Wallenberg Foundation, the Swedish Research Council, and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515.

Published
2018

23. Probing Narrow-Line Seyfert 1 Galaxies In The Southern Hemisphere

Author

Chen, Sina, Berton, Marco, La Mura, Giovanni, Congiu, Enrico, Cracco, Valentina, Fan, Junhui, Ciroi, Stefano, Rafanelli, Piero, and Bastieri, Denis

Subjects
NLS1, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

In this talk, I will present a new accurate catalog of narrow-line Seyfert 1 galaxies (NLS1s) in the southern hemisphere from the Six-degree Field Galaxy Survey (6dFGS) final data release, which is currently the most extensive spectroscopic survey available in the southern sky whose database has not yet been systematically explored. We classified 167 sources as NLS1s based on their optical spectral properties. We derived flux-calibrated spectra for the first time that the 6dFGS indeed does not provide. By analyzing these spectra, we obtained strong correlations between the monochromatic luminosity at 5100 Angstrom and the luminosity of Hβ and [O III]λ5007 lines. The estimated central black hole mass and Eddington ratio have an average value of 9.55×106M⊙ and 0.90LEdd respectively, which is a typical value for NLS1s. In the sample, 23 (13.8%) NLS1s were detected at radio frequencies, and 10 (6.0%) of them are radio-loud. Our results confirmed that radio-loud sources tend to have higher redshift, more massive black hole, and higher radio and optical luminosity than radio-quiet sources. In this work, we increased the number of NLS1 galaxies and confirmed some well known properties of this class of AGN. This new NLS1 sample can be carried out with advanced telescopes in the southern hemisphere, such as the Extremely Large Telescope (ELT), the Atacama Large Millimeter/submillimeter Array (ALMA), and the Square Kilometre Array (SKA), for the purpose of investigating the peculiarity of NLS1s, with respect to other AGN.

Published
2018
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24. The Sub-TeV transient Gamma-Ray sky: challenges and opportunities

Author

La Mura, Giovanni, primary, Assis, Pedro, additional, Blanco, Alberto, additional, Conceição, Rúben, additional, Fonte, Paulo, additional, LOPES, Luis, additional, Pimenta, Mário, additional, Tomé, Bernardo, additional, Espírito Santo, Catarina, additional, Mendes, Luis, additional, Ferreira, Miguel, additional, Abreu, Pedro, additional, Brogueira, Pedro, additional, Mendes, Luis Filipe, additional, Barão, Fernando, additional, Barres de Almeida, Ulisses, additional, Shellard, Ronald, additional, GIACCARI, Ugo, additional, Lippmann, Otto, additional, D’Ettorre Piazzoli, Benedetto, additional, Doro, Michele, additional, Prandini, Elisa, additional, Perennes, Cédric, additional, Matthiae, Giorgio, additional, Tavani, Marco, additional, Santonico, Rinaldo, additional, De Angelis, Alessandro, additional, Coto, Ruben Lopez, additional, Chiavassa, Andrea, additional, Vicha, Jakub, additional, Travnicek, Petr, additional, and Di Sciascio, Giuseppe, additional

Published
2019
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26. The link between X-ray complexity and optical lines in NLS1s

Author

Vietri, Amelia, primary, Berton, Marco, additional, Ciroi, Stefano, additional, Congiu, Enrico, additional, Chen, Sina, additional, Cracco, Valentina, additional, Cattapan, Arianna, additional, Frezzato, Michele, additional, La Mura, Giovanni, additional, Peruzzi, Tobia, additional, and Rafanelli, Piero, additional

Published
2018
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28. Broad-band properties of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

Author

Foschini, L., Berton, Marco, Caccianiga, A., Ciroi, Stefano, Cracco, Valentina, Peterson, B. M., Angelakis, E., Braito, V., Fuhrmann, L., Gallo, L., Grupe, D., Järvelä, E., Kaufmann, S., Komossa, S., Kovalev, Y. Y., Lähteenmäki, A., Lisakov, M. M., Lister, M. L., Mathur, S., Richards, J. L., Romano, P., Sievers, A., Tagliaferri, G., Tammi, J., Tibolla, O., Tornikoski, M., Vercellone, S., LA MURA, Giovanni, Maraschi, L., and Rafanelli, Piero

Subjects
astro-ph.HE, High Energy Astrophysical Phenomena (astro-ph.HE), Computer Science::Sound, astro-ph.GA, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, Astrophysics::Galaxy Astrophysics
Abstract

We report about recent updates of broad-band properties of radio-loud narrow-line Seyfert 1 galaxies., Comment: 5 pages, no figures. Proceedings 28th Texas Symposium on Relativistic Astrophysics, Geneva (Switzerland), 13-18 December 2015

Published
2016
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29. Multiwavelength survey of a sample of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

Author

Foschini, L., Berton, Marco, Caccianiga, A., Ciroi, Stefano, Cracco, Valentina, Peterson, B. M., Angelakis, E., Braito, V., Fuhrmann, L., Gallo, L., Grupe, D., Järvelä, E., Kaufmann, S., Komossa, S., Kovalev, Y. Y., Lähteenmäki, A., Lisakov, M. M., Lister, M. L., Mathur, S., Richards, J. L., Romano, P., Sievers, A., Tagliaferri, G., Tammi, J., Tibolla, O., Tornikoski, M., Vercellone, S., LA MURA, Giovanni, Maraschi, L., and Rafanelli, Piero

Subjects
astro-ph.HE, High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.GA, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, Astrophysics::Galaxy Astrophysics
Abstract

We report on a multiwavelength survey of a sample of 42 flat-spectrum radio-loud narrow-line Seyfert 1 galaxies (RLNLS1s). This is the largest known sample of this type of active galactic nucleus (AGN) to date. We found that 17% of sources were detected at high-energy gamma rays (E>100 MeV), and 90% at X-rays (0.3-10 keV). The masses of the central black holes are in the range $\sim 10^{6-8}M_{\odot}$, smaller than the values of blazars. The disk luminosities are about 1-49% of the Eddington value, with one outlier at 0.3%, comparable with the luminosities observed in flat-spectrum radio quasars (FSRQs). The jet powers are $\sim 10^{42-46}$ erg s$^{-1}$, comparable with BL Lac Objects, yet relatively smaller than FSRQs. However, once renormalized by the mass of the central black hole, the jet powers of RLNLS1s, BL Lacs, and FSRQs are consistent each other, indicating the scalability of the jets. We found episodes of extreme variability at high energies on time scales of hours. In some cases, dramatic spectral and flux changes are interpreted as the interplay between the relativistic jet and the accretion disk. We conclude that, despite the distinct observational properties, the central engines of RLNLS1s are similar to those of blazars., 4 pages, 1 figure. Poster presented at HEPRO V (5-8 October 2015, La Plata, Argentina). Version for Proceedings

Published
2015

31. Extended Narrow-Line Region in Seyfert Galaxies

Author

Congiu, Enrico, primary, Contini, Marcella, additional, Ciroi, Stefano, additional, Cracco, Valentina, additional, Di Mille, Francesco, additional, Berton, Marco, additional, Frezzato, Michele, additional, La Mura, Giovanni, additional, and Rafanelli, Piero, additional

Published
2017
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33. Long-Term Monitoring of the Broad-Line Region Properties in a Selected Sample of AGN

Author

Ilić, Dragana, primary, Shapovalova, Alla I., additional, Popović, Luka Č., additional, Chavushyan, Vahram, additional, Burenkov, Alexander N., additional, Kollatschny, Wolfram, additional, Kovačević, Andjelka, additional, Marčeta-Mandić, Sladjana, additional, Rakić, Nemanja, additional, La Mura, Giovanni, additional, and Rafanelli, Piero, additional

Published
2017
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35. Relativistic plasmas in AGN jets

Author

La Mura, Giovanni, primary, Busetto, Giovanni, additional, Ciroi, Stefano, additional, Rafanelli, Piero, additional, Berton, Marco, additional, Congiu, Enrico, additional, Cracco, Valentina, additional, and Frezzato, Michele, additional

Published
2017
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39. Physical Properties of the Broad-line Region

Author

Ilic, D, LA MURA, Giovanni, Popovic, L. C., Shapovalova, A. I., Ciroi, Stefano, Chavushyan, V. H., Rafanelli, Piero, Burenkov, A. N., and Marcado, A.

Published
2007

40. Introducing CUBES: the Cassegrain U-band Brazil-ESO spectrograph

Author

Bristow, Paul, additional, Barbuy, Beatriz, additional, Macanhan, Vanessa B., additional, Castilho, Bruno, additional, Dekker, Hans, additional, Delabre, Bernard, additional, Diaz, Marcos, additional, Gneiding, Clemens, additional, Kerber, Florian, additional, Kuntschner, Harald, additional, La Mura, Giovanni, additional, Reiss, Roland, additional, and Vernet, J., additional

Published
2014
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42. Nuclear activity and stellar mass in galaxies

Author

La Mura, Giovanni, primary, Bindoni, Daniele, additional, Ciroi, Stefano, additional, Cracco, Valentina, additional, Rafanelli, Piero, additional, Vaona, Luigi, additional, and D'Abrusco, Raffaele, additional

Published
2013
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43. Optical Counterparts of Undetermined Type γ -Ray Active Galactic Nuclei with Blazar-Like Spectral Energy Distributions.

Author

La Mura, Giovanni, Chiaro, Graziano, Ciroi, Stefano, Rafanelli, Piero, Salvetti, David, Berton, Marco, and Cracco, Valentina

Subjects
*ACTIVE galactic nuclei, *BL Lacertae objects, *SPECTRAL energy distribution, *ASTRONOMICAL observations, *X-ray emission spectroscopy, *PHOTONS
Abstract

During its first four years of scientific observations, the Fermi Large Area Telescope (Fermi-LAT) detected 3033 γ -ray sources above a 4σ significance level. Although most of the extra-galactic sources are active galactic nuclei (AGN) of the blazar class, other families of AGNs are observed too, while a still high fraction of detections (~30%) remains with uncertain association or classification. According to the currently accepted interpretation, the AGN γ -ray emission arises from inverse Compton (IC) scattering of low energy photons by relativistic particles confined in a jet, which, in the case of blazars, is oriented very close to our line-of-sight. Taking advantage of data from radio and X-ray wavelengths, which we expect to be produced together with γ-rays, providing a much better source localization potential, we focused our attention on a sample of γ -ray Blazar Candidates of Undetermined type (BCUs), starting a campaign of optical spectroscopic observations. The main aims of our investigation include a census of the AGN families that contribute to γ -ray emission and a study of their redshift distribution, with the subsequent implications on the intrinsic source power.We furthermore analyze which γ -ray properties can better constrain the nature of the source, thus helping in the study of objects not yet associated with a reliable low frequency counterpart. Here we report on the instruments and techniques used to identify the optical counterparts of γ -ray sources, we give an overview on the status of our work, and we discuss the implications of a large scale study of γ -ray emitting AGNs. [ABSTRACT FROM AUTHOR]

Published
2015
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48. Einstein@Home discovers a radio-quiet gamma-ray millisecond pulsar.

Author

Clark CJ, Pletsch HJ, Wu J, Guillemot L, Kerr M, Johnson TJ, Camilo F, Salvetti D, Allen B, Anderson D, Aulbert C, Beer C, Bock O, Cuéllar A, Eggenstein HB, Fehrmann H, Kramer M, Kwang SA, Machenschalk B, Nieder L, Ackermann M, Ajello M, Baldini L, Ballet J, Barbiellini G, Bastieri D, Bellazzini R, Bissaldi E, Blandford RD, Bloom ED, Bonino R, Bottacini E, Brandt TJ, Bregeon J, Bruel P, Buehler R, Burnett TH, Buson S, Cameron RA, Caputo R, Caraveo PA, Cavazzuti E, Cecchi C, Charles E, Chekhtman A, Ciprini S, Cominsky LR, Costantin D, Cutini S, D'Ammando F, De Luca A, Desiante R, Di Venere L, Di Mauro M, Di Lalla N, Digel SW, Favuzzi C, Ferrara EC, Franckowiak A, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Giglietto N, Giordano F, Giroletti M, Gomez-Vargas GA, Green D, Grenier IA, Guiriec S, Harding AK, Hewitt JW, Horan D, Jóhannesson G, Kensei S, Kuss M, La Mura G, Larsson S, Latronico L, Li J, Longo F, Loparco F, Lovellette MN, Lubrano P, Magill JD, Maldera S, Manfreda A, Mazziotta MN, McEnery JE, Michelson PF, Mirabal N, Mitthumsiri W, Mizuno T, Monzani ME, Morselli A, Moskalenko IV, Nuss E, Ohsugi T, Omodei N, Orienti M, Orlando E, Palatiello M, Paliya VS, de Palma F, Paneque D, Perkins JS, Persic M, Pesce-Rollins M, Porter TA, Principe G, Rainò S, Rando R, Ray PS, Razzano M, Reimer A, Reimer O, Romani RW, Saz Parkinson PM, Sgrò C, Siskind EJ, Smith DA, Spada F, Spandre G, Spinelli P, Thayer JB, Thompson DJ, Torres DF, Troja E, Vianello G, Wood K, and Wood M

Abstract

Millisecond pulsars (MSPs) are old neutron stars that spin hundreds of times per second and appear to pulsate as their emission beams cross our line of sight. To date, radio pulsations have been detected from all rotation-powered MSPs. In an attempt to discover radio-quiet gamma-ray MSPs, we used the aggregated power from the computers of tens of thousands of volunteers participating in the Einstein@Home distributed computing project to search for pulsations from unidentified gamma-ray sources in Fermi Large Area Telescope data. This survey discovered two isolated MSPs, one of which is the only known rotation-powered MSP to remain undetected in radio observations. These gamma-ray MSPs were discovered in completely blind searches without prior constraints from other observations, raising hopes for detecting MSPs from a predicted Galactic bulge population.

Published
2018
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