Abstracts of Interest
Selected by:
Abstract: 1903.09545
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:Investigating the dark matter signal in the cosmic ray antiproton flux with the machine learning method
(Submitted on 22 Mar 2019)
Abstract: We investigate the implications on the dark matter (DM) signal from the AMS-02 cosmic antiproton flux. Global fits to the data are performed under different propagation and hadronic interaction models. The uncertainties from the injection spectrum, propagation effects and solar modulation of the cosmic rays are taken into account comprehensively. Since we need to investigate extended parameter regions with multiple free parameters in the fit, the machine learning method is adopted to maintain a realistic time cost. We find all the effects considered in the fitting process interplay with each other, among which the hadronic interaction model is the most important factor affecting the result. In most hadronic interaction and CR propagation models no DM signal is found with significance larger than $2\sigma$ except that the EPOS-LHC interaction model requires a more than $3\sigma$ DM signal with DM mass around $1\,\mathrm{TeV}$. For the diffusive reacceleration propagation model there is a highly significant DM signal with mass around $100\,\mathrm{GeV}$. However, the signal becomes less than $1\sigma$ if we take a charge dependent solar modulation potential in the analysis.
Abstract: 1903.09273
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:$ν\texttt{bhlight}$: Radiation GRMHD for Neutrino-Driven Accretion Flows
(Submitted on 21 Mar 2019)
Abstract: The 2017 detection of the in-spiral and merger of two neutron stars was a landmark discovery in astrophysics. We now know that such mergers are central engines of short gamma ray bursts and sites of r-process nucleosynthesis, where the heaviest elements in our universe are formed. In the coming years, we expect many more such mergers. Modeling such systems presents a significant computational challenge along with the observational one. To meet this challenge, we present $\nu\texttt{bhlight}$, a scheme for solving general relativistic magnetohydrodynamics with energy-dependent neutrino transport in full (3+1)-dimensions, facilitated by Monte Carlo methods. We present a suite of tests demonstrating the accuracy, efficacy, and necessity of our scheme. We demonstrate the potential of our scheme by running a sample calculation in a domain of interest---the dynamics and composition of the accretion disk formed by a binary neutron star merger.
Abstract: 1903.09187
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:Big Bang Nucleosynthesis and Neutrino Cosmology
(Submitted on 21 Mar 2019)
Abstract: There exist a range of exciting scientific opportunities for Big Bang Nucleosynthesis (BBN) in the coming decade. BBN, a key particle astrophysics "tool" for decades, is poised to take on new capabilities to probe beyond standard model (BSM) physics. This development is being driven by experimental determination of neutrino properties, new nuclear reaction experiments, advancing supercomputing/simulation capabilities, the prospect of high-precision next-generation cosmic microwave background (CMB) observations, and the advent of 30m class telescopes.
Abstract: 1903.09041
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:X-ray absorbing column densities of a complete sample of short Gamma Ray Bursts
(Submitted on 21 Mar 2019)
Abstract: We update a flux-limited complete sample of Swift-based SGRBs (SBAT4, D'Avanzo et al. 2014), bringing it to 25 events and doubling its previous redshift range. We then evaluate the column densities of the events in the updated sample, in order to compare them with the NH distribution of LGRBs, using the sample BAT6ext (Arcodia et al. 2016). We rely on Monte Carlo simulations of the two populations and compare the computed NH distributions with a two sample Kolmogorov Smirnov (K-S) test. We then study how the K-S probability varies with respect to the redshift range we consider. We find that the K-S probability keeps decreasing as redshift increases until at z$\sim$1.8 the probability that short and long GRBs come from the same parent distribution drops below 1$\%$. This testifies for an observational difference among the two populations. This difference may be due to the presence of highly absorbed LGRBs above z$\sim$1.3, which have not been observed in the SGRB sample yet, although this may be due to our inability to detect them, or to the relatively small sample size.
Abstract: 1903.08986
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:"Auxiliary" Science with the WFIRST Microlensing Survey
(Submitted on 21 Mar 2019)
Abstract: The Wide Field Infrared Survey Telescope (WFIRST) will monitor $\sim 2$ deg$^2$ toward the Galactic bulge in a wide ($\sim 1-2~\mu$m) W149 filter at 15-minute cadence with exposure times of $\sim$50s for 6 seasons of 72 days each, for a total $\sim$41,000 exposures taken over $\sim$432 days, spread over the 5-year prime mission. This will be one of the deepest exposures of the sky ever taken, reaching a photon-noise photometric precision of 0.01 mag per exposure and collecting a total of $\sim 10^9$ photons over the course of the survey for a W149$_{\rm AB}\sim 21$ star. Of order $4 \times 10^7$ stars will be monitored with W149$_{\rm AB}$<21, and 10$^8$ stars with W145$_{\rm AB}$<23. The WFIRST microlensing survey will detect $\sim$54,000 microlensing events, of which roughly 1% ($\sim$500) will be due to isolated black holes, and $\sim$3% ($\sim$1600) will be due to isolated neutron stars. It will be sensitive to (effectively) isolated compact objects with masses as low as the mass of Pluto, thereby enabling a measurement of the compact object mass function over 10 orders of magnitude. Assuming photon-noise limited precision, it will detect $\sim 10^5$ transiting planets with sizes as small as $\sim 2~R_\oplus$, perform asteroseismology of $\sim 10^6$ giant stars, measure the proper motions to $\sim 0.3\%$ and parallaxes to $\sim 10\%$ for the $\sim 6 \times 10^6$ disk and bulge stars in the survey area, and directly detect $\sim 5 \times 10^3$ Trans-Neptunian objects (TNOs) with diameters down to $\sim 10$ km, as well as detect $\sim 10^3$ occulations of stars by TNOs during the survey. All of this science will completely serendipitous, i.e., it will not require modifications of the WFIRST optimal microlensing survey design. Allowing for some minor deviation from the optimal design, such as monitoring the Galactic center, would enable an even broader range of transformational science.
Abstract: 1903.08982
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:Magnetic Reconnection, Cosmic Ray Acceleration, and Gamma-Ray emission around Black Holes and Relativistic Jets
(Submitted on 19 Mar 2019)
Abstract: Particle acceleration by magnetic reconnection is now recognized as an important process in magnetically dominated regions of galactic and extragalactic black hole sources. This process helps to solve current puzzles specially related to the origin of the very high energy flare emission in these sources. In this review, we discuss this acceleration mechanism and show recent analytical studies and multidimensional numerical SRMHD and GRMHD (special and general relativistic magnetohydrodynamical) simulations with the injection of test particles, which help us to understand this process both in relativistic jets and coronal regions of these sources. The very high energy and neutrino emission resulting from the accelerated particles by reconnection is also discussed.
Abstract: 1903.08848
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:Exploring neutrino mass and mass hierarchy in interacting dark energy models
(Submitted on 21 Mar 2019)
Abstract: We investigate how the dark energy properties impact the constraints on the total neutrino mass in interacting dark energy (IDE) models. In this study, we focus on two typical interacting dynamical dark energy models, i.e., the I$w$CDM model and the IHDE model. To avoid the large-scale instability problem in IDE models, we apply the parameterized post-Friedmann (PPF) approach to calculate the perturbation of dark energy. We employ the Planck 2015 CMB temperature and polarization data, combined with low-redshift measurements on baryon acoustic oscillation distance scales, type Ia supernovae, and the Hubble constant, to constrain the cosmological parameters. We find that the dark energy properties could influence the constraint limits on the total neutrinos mass. Once dynamical dark energy is considered in the IDE models, the upper bounds of $\sum m_\nu$ will be changed. By considering the values of $\chi^2_{\rm min}$, we find that in these IDE models the NH case is slightly preferred over the IH case; for example, the difference of $\Delta\chi^2=2.720$ is given in the IHDE+$\sum m_\nu$ model. In addition, we also find that in the I$w$CDM+$\sum m_\nu$ model $\beta=0$ is consistent with current observational data inside the 1$\sigma$ range, and in the IHDE+$\sum m_\nu$ model $\beta>0$ is favored at more than the 2$\sigma$ level.
Abstract: 1903.08750
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:Coherent transition radiation from the geomagnetically-induced current in cosmic-ray air showers: Implications for the anomalous events observed by ANITA
(Submitted on 20 Mar 2019)
Abstract: We show that coherent transition radiation (CTR) from the electrically-neutral transverse geomagnetic current (CTR-GM) has to be included in the radio emission models to understand the radio emission from a high-energy cosmic-ray air shower traversing a dielectric boundary. We demonstrate that for zenith angles less than roughly 70 degrees, combined with high surface elevation the inclusion of CTR-GM can significantly alter the emitted electric field. As such CTR-GM might provide a natural, standard model, explanation to the recent "anomalous" events observed by the ANITA detector.
Abstract: 1903.08714
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:The Astrophysical Multimessenger Observatory Network (AMON)
(Submitted on 20 Mar 2019)
Abstract: The Astrophysical Multimessenger Observatory Network (AMON) has been built with the purpose of enabling near real-time coincidence searches between different observatories and telescopes. Its mission is to evoke, exploit and explore multimessenger sources. AMON aims to promote the advancement of multimessenger astrophysics by allowing its participants to study the most energetic phenomena in the universe and to help answer some of the outstanding enigmas in astrophysics, fundamental physics, and cosmology. The main strength of AMON is its ability to combine and analyze sub-threshold data from different facilities. These data cannot generally be used standalone to identify astrophysical sources. The analysis algorithms used in AMON will identify statistically significant coincidence candidates of multimessenger events, leading to the distribution of AMON alerts used by partner observatories for real-time follow-up to catch transient events. We present the science motivation, partner observatories, implementation and summary of the current status of the AMON project.
Abstract: 1903.08657
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:A 2019 Cosmic UV/X-ray Background Model Update
(Submitted on 20 Mar 2019)
Abstract: We present an updated model of the cosmic ionizing background from the UV to the X-rays. Relative to our previous model (Faucher-Giguere et al. 2009), the new model provides a better fit to a large number of up-to-date empirical constraints, including: 1) new galaxy UV luminosity functions; 2) stellar spectra including binary stars; 3) recent escape fraction measurements; 4) a measurement of the non-ionizing UV background; 5) obscured and unobscured AGN; 6) measurements of the intergalactic HI and HeII photoionization rates at z~0-6; and 7) the local X-ray background. In this model, AGN dominate the HI ionizing background at z<3 and star-forming galaxies dominate it at higher redshifts. Combined with the large AGN contribution at low redshifts and the steeply declining AGN luminosity function beyond z~2, the slow evolution of the HI ionization rate inferred from the HI Lya forest requires an escape fraction from star-forming galaxies that increases strongly with redshift. Our new UV background model implies a best-fit escape fraction of 7% at z=3. We provide effective photoionization and photoheating rates calibrated to match the Planck 2018 reionization optical depth and recent constraints from the HeII Lya forest.
Abstract: 1903.08607
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:Neutrino Echoes from Multimessenger Transient Sources
(Submitted on 20 Mar 2019 (v1), last revised 21 Mar 2019 (this version, v2))
Abstract: The detection of the high-energy neutrino event, IceCube-170922A, demonstrated that multimessenger particle astrophysics trigged by neutrino alerts is feasible. We consider time delay signatures caused by secret neutrino interactions with the cosmic neutrino background and dark matter, and suggest that these can be used as a new probe of neutrino interactions beyond the Standard Model (BSM). The tests with BSM-induced neutrino echoes are distinct from existing constraints from the spectral modification, and will be enabled by multimessenger observations of bright neutrino transients with future experiments such as IceCube-Gen2, KM3Net and Hyper-Kamiokande.
Abstract: 1903.08473
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:CRPropa - A Toolbox for Cosmic Ray Simulations
(Submitted on 20 Mar 2019)
Abstract: The astrophysical interpretation of recent experimental observations of cosmic rays relies increasingly on Monte Carlo simulations of cosmic ray propagation and acceleration. Depending on the energy range of interest, several different propagation effects inside the Milky Way as well as in extragalactic space have to be taken into account when interpreting the data. With the CRPropa framework we aim to provide a toolbox for according simulations. In recent versions of CRPropa, the ballistic single particle propagation mode aiming primarily at extragalactic cosmic rays has been complemented by a solver for the differential transport equation to address propagation of galactic cosmic rays. Additionally, modules have been developed to address cosmic ray acceleration and many improvements have been added for simulations of electromagnetic secondaries. In this contribution we will give an overview of the CRPropa simulation framework with a focus on the latest improvements and highlight selected features by example applications.
Abstract: 1903.08195
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:Gender and the Career Outcomes of PhD Astronomers in the United States
(Submitted on 19 Mar 2019)
Abstract: I analyze the postdoctoral career tracks of a nearly-complete sample of astronomers from 28 United States graduate astronomy and astrophysics programs spanning 13 graduating years (N=1063). A majority of both men and women (65% and 66%, respectively) find long-term employment in astronomy or closely-related academic disciplines. No significant difference is observed in the rates at which men and women are hired into these jobs following their PhDs, or in the rates at which they leave the field. Applying a two-outcome survival analysis model to the entire data set, the relative academic hiring probability ratio for women vs. men at a common year post-PhD is H_(F/M) = 1.08 (+0.20, -0.17; 95% CI); the relative leaving probability ratio is L_(F/M) = 1.03 (+0.31, -0.24). These are both consistent with equal outcomes for both genders (H_(F/M) = L_(F/M) = 1) and rule out more than minor gender differences in hiring or in the decision to abandon an academic career. They suggest that despite discrimination and adversity, women scientists are successful at managing the transition between PhD, postdoctoral, and faculty/staff positions.
Abstract: 1903.07972
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:A new hard X-ray selected sample of extreme high-energy peaked BL Lac objects and their TeV gamma-ray properties
(Submitted on 19 Mar 2019)
Abstract: Extreme high-energy peaked BL Lac objects (EHBLs) are an emerging class of blazars with exceptional spectral properties. The non-thermal emission of the relativistic jet peaks in the spectral energy distribution (SED) plot with the synchrotron emission in X-rays and with the gamma-ray emission in the TeV range or above. These high photon energies may represent a challenge for the standard modeling of these sources. They are important for the implications on the indirect measurements of the extragalactic background light, the intergalactic magnetic field estimate, and the possible origin of extragalactic high-energy neutrinos. In this paper, we perform a comparative study of the multi-wavelength spectra of 32 EHBL objects detected by the Swift-BAT telescope in the hard X-ray band and by the Fermi-LAT telescope in the high-energy gamma-ray band. The source sample presents uniform spectral properties in the broad-band SEDs, except for the TeV gamma-ray band where an interesting bimodality seems to emerge. This suggests that the EHBL class is not homogeneous, and a possible sub-classification of the EHBLs may be unveiled. Furthermore, in order to increase the number of EHBLs and settle their statistics, we discuss the potential detectability of the 14 currently TeV gamma-ray undetected sources in our sample by the Cherenkov telescopes.
Abstract: 1903.07897
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:Fermi-LAT Observations of Extreme Spectral Variability in IC 310
(Submitted on 19 Mar 2019)
Abstract: We investigate the physical mechanisms of high-energy gamma-ray emission from the TeV-emitting misaligned active galactic nucleus IC 310. Eight years of data from the Fermi Large Area Telescope (Fermi-LAT) between 100 MeV and 500 GeV are reduced and analysed to study the temporal and spectral characteristics of IC 310. Point spread function-partitioned instrument response functions are used to improve the resolvability of IC 310 from nearby NGC 1275. Systematic effects due to this choice of instrument response functions and the proximity of NGC 1275 are investigated. We find strong spectral variability and detect the hard flaring state of IC 310 along with a previously undiscovered soft state in quiescent periods, and the first detection with Fermi-LAT below 1 GeV. This represents a shift in peak Compton energy of more than five orders of magnitude. Possible interpretations are discussed, but we lack the instantaneous sensitivity with Fermi to probe the underlying physics.
Abstract: 1903.07760
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:High-Energy Astrophysics in the 2020s and Beyond
(Submitted on 18 Mar 2019)
Abstract: With each passing decade, we gain new appreciation for the dynamic, connected, and often violent nature of the Universe. This reality necessarily places the study of high-energy processes at the very heart of modern astrophysics. This White Paper illustrates the central role of high-energy astrophysics to some of the most pressing astrophysical problems of our time, the formation/evolution of galaxies, the origin of the heavy elements, star and planet formation, the emergence of life on exoplanets, and the search for new physics. We also highlight the new connections that are growing between astrophysicists and plasma physicists. We end with a discussion of the challenges that must be addressed to realize the potential of these connections, including the need for integrated planning across physics and astronomy programs in multiple agencies, and the need to foster the creativity and career aspirations of individual scientists in this era of large projects.
Abstract: 1903.07713
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:High-Energy Galactic Cosmic Rays (Astro2020 Science White Paper)
(Submitted on 18 Mar 2019)
Abstract: The origin of the highest energy Galactic cosmic rays is still not understood, nor is the transition to EeV extragalactic particles. Scientific progress requires enhancements of existing air-shower arrays, such as: IceCube with its surface detector IceTop, and the low-energy extensions of both the Telescope Array and the Pierre Auger Observatory.
Abstract: 1903.07651
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:XMM-Newton and Chandra observations of the unidentified Fermi-LAT source 3FGL J1016.5-6034: A Young Pulsar with a Nebula?
(Submitted on 18 Mar 2019)
Abstract: We report the discovery of a bright X-ray source in the XMM-Newton and Chandra X-ray Observatory (CXO) images of the unidentified Fermi-LAT source 3FGL J1016.5-6034. The XMM-Newton spectrum of the source is well fit by an absorbed blackbody+power-law model with a temperature, $kT=0.20\pm0.02$ keV, and photon index $\Gamma=1.8\pm0.1$. The CXO resolves the same source into a point source (CXOU J101546.0-602939) and a surrounding compact nebula seen up to about $30''$ from the point source. The CXO spectrum of the nebula can be described by an absorbed power-law with $\Gamma=1.7\pm0.3$ and is partly responsible for the non-thermal emission observed in the XMM-Newton spectrum. The XMM-Newton images also reveal faint extended emission on arcminute scales. These properties strongly suggest that the X-ray source and the accompanying extended emission are a newly discovered young pulsar with a pulsar wind nebula. We also analyze $\sim10$ years of Fermi-LAT data and find that the improved LAT source localization is consistent with the position of CXOU J101546.0-602939.
Abstract: 1903.07527
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:The Energy-dependent $γ$-ray Morphology of the Crab Nebula Observed with the Fermi Large Area Telescope
(Submitted on 18 Mar 2019)
Abstract: The Crab Nebula is a bright emitter of non-thermal radiation across the entire accessible range of wavelengths. The spatial and spectral structures of the synchrotron nebula are well-resolved from radio to hard X-ray emission. The un-pulsed emission at GeV to TeV energies is mostly produced via inverse-Compton scattering of energetic electrons with the synchrotron-emitted photons. The spatial structure observed at these energies provides insights into the distribution of electrons and indirectly constrains the so-far unknown structure of the magnetic field in the nebula. Analyzing the LAT data accumulated over $\sim$9.1 years with a properly refined model for the Crab pulsar's spectrum, we determined the 68\% containment radius ($R_{68}$) of the Crab Nebula to be $({0.0330\pm0.0025_{stat}}{^{+0.0012}_{-0.0075}}_{sys})^\circ$ (${1.98'\pm0.15'_{stat}}{^{+0.07'}_{-0.45'}}_{sys}$) in the 5--500 GeV band. The estimated systematic uncertainty is based on two factors: (1) different analysis methods, morphological models and event types, and (2) the point-spread-function evaluated with observations of Mkn 421. When comparing the \emph{Fermi} LAT and H.E.S.S. results on the spatial extension, we find evidence for an energy-dependent shrinking of the Crab Nebula's $\gamma$-ray extension ($R_{68}\propto E_\mathrm{IC}^{-\alpha}$ where $\alpha=0.155\pm0.035_{stat}{-0.037}_{sys}$).
Abstract: 1903.07460
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:Tunka Advanced Instrument for cosmic rays and Gamma Astronomy
(Submitted on 18 Mar 2019)
Abstract: The paper is a script of a lecture given at the ISAPP-Baikal summer school in 2018. The lecture gives an overview of the Tunka Advanced Instrument for cosmic rays and Gamma Astronomy (TAIGA) facility including historical introduction, description of existing and future setups, and outreach and open data activities.
Abstract: 1903.06989
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:A Catalog of Redshift Estimates for 1366 BATSE Long-Duration Gamma-Ray Bursts: Evidence for Strong Selection Effects on the Phenomenological Prompt Gamma-Ray Correlations
(Submitted on 16 Mar 2019)
Abstract: We present a catalog of the redshift estimates and probability distributions for 1366 individual Long-duration Gamma-Ray Bursts (LGRBs) detected by the Burst And Transient Source Experiment (BATSE). This result is based on a careful classification and modeling of the population distribution of BATSE LGRBs in the 5-dimensional space of redshift as well as intrinsic prompt gamma-ray emission properties: peak luminosity, total isotropic emission, the spectral peak energy, and the intrinsic duration, while taking into account the detection mechanism of BATSE and sample incompleteness. The underlying assumption in our modeling approach is that LGRBs trace the Cosmic Star Formation Rate and that the joint 4-dimensional distribution of the aforementioned prompt gamma-ray emission properties follows a multivariate log-normal distribution. Our modeling approach enables us to constrain the redshifts of BATSE LGRBs to average uncertainty ranges of $0.7$ and $1.7$ at $50\%$ and $90\%$ confidence levels, respectively. Our predictions are almost entirely at odds with the previous estimates of BATSE redshifts based on the phenomenological high-energy correlations, in particular with the estimates derived from the lag-luminosity and the variability-luminosity relations. There is, however, a weak but significant correlation of strength $\sim0.26$ between our predicted redshift estimates and those derived from the hardness-brightness relations. The discrepancies between the estimates can be explained by the strong influence of sample incompleteness in shaping the phenomenologically proposed high-energy correlations in the literature. The presented catalog here can be useful for demographic studies of LGRBs and studies of individual BATSE events.
Abstract: 1903.06957
Full Text: [ PostScript, PDF]
Full Text: [ PostScript, PDF]
Title:The Second AGILE Catalog of Gamma-Ray Sources
(Submitted on 16 Mar 2019)
Abstract: Aims. We present the second AGILE-GRID Catalog (2AGL) of {\gamma}-ray sources in the 100 MeV-10 GeV energy range. Methods. With respect to previous AGILE-GRID catalogs, the current 2AGL Catalog is based on the first 2.3 years of science data from the AGILE mission (the so called 'pointing mode') and incorporates more data and several analysis improvements, including better calibrations at the event reconstruction level, an updated model for the Galactic diffuse gamma-ray emission, a refined procedure for point-like source detection, and the inclusion of a search for extended {\gamma}-ray sources. Results. The 2AGL Catalog includes 175 high-confidence sources (above 4{\sigma} significance) with their location regions and spectral properties, and a variability analysis with 4-day light curves for the most significant ones. Relying on the error region of each source position, including systematic uncertainties, 121 sources are considered as positionally associated with known couterparts at different wavelengths or detected by other {\gamma}-ray instruments. Among the identified or associated sources, 62 are Active Galactic Nuclei (AGNs) of the blazar class. Pulsars represent the largest Galactic source class, with 40 associated pulsars, 7 of them with detected pulsation; 8 Supernova Remnants and 4 high-mass X-ray binaries have also been identified. A substantial number of 2AGL sources are unidentified: for 54 sources no known counterpart is found at different wavelengths. Among these sources, we discuss a sub-class of 29 AGILE-GRID-only {\gamma}-ray sources that are not present in 1FGL, 2FGL or 3FGL catalogs; the remaining sources are unidentified in both 2AGL and 3FGL Catalogs. We also present an extension of the analysis of 2AGL sources detected in the 50-100 MeV energy range.
This page created: Mon Mar 25 15:45:01 ACDT 2019 by ecbronca
For a printable title listing click here
For details on generating this page see the instructions. If there are problems with this page (and I expect there will be from time to time) contact Jose.
For previous lists of abstracts of interest click Previous abstracts of interest