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1. Search for Extended GeV Sources in the Inner Galactic Plane

Author

Abdollahi, S., Acero, F., Acharyya, A., Adelfio, A., Ajello, M., Baldini, L., Ballet, J., Bartolini, C., Gonzalez, J. Becerra, Bellazzini, R., Bissaldi, E., Bonino, R., Bruel, P., Cameron, R. A., Caraveo, P. A., Castro, D., Cavazzuti, E., Cheung, C. C., Cibrario, N., Ciprini, S., Cozzolongo, G., Orestano, P. Cristarella, Cuoco, A., Cutini, S., D'Ammando, F., Di Lalla, N., Dinesh, A., Di Venere, L., Domínguez, A., Fiori, A., Funk, S., Fusco, P., Gargano, F., Gasbarra, C., Gasparrini, D., Germani, S., Giacchino, F., Giglietto, N., Giliberti, M., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guillemot, L., Guiriec, S., Gupta, R., Hashizume, M., Hays, E., Hewitt, J. W., Horan, D., Hou, X., Kayanoki, T., Kuss, M., Laviron, A., Lemoine-Goumard, M., Liguori, A., Li, J., Liodakis, I., Loizzo, P., Longo, F., Loparco, F., Lorusso, L., Lovellette, M. N., Lubrano, P., Maldera, S., Malyshev, D., Martí-Devesa, G., Martin, P., Mazziotta, M. N., Mereu, I., Michelson, P. F., Mirabal, N., Mitthumsiri, W., Mizuno, T., Monti-Guarnieri, P., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Omodei, N., Orienti, M., Orlando, E., Paneque, D., Panzarini, G., Persic, M., Pesce-Rollins, M., Pillera, R., Porter, T. A., Rainò, S., Rando, R., Razzano, M., Reimer, A., Reimer, O., Bernal, M. Rocamora, Sánchez-Conde, M., Parkinson, P. M. Saz, Serini, D., Sgrò, C., Siskind, E. J., Smith, D. A., Spandre, G., Spinelli, P., Strong, A. W., Suson, D. J., Tajima, H., Thayer, J. B., Torres, D. F., Valverde, J., Wadiasingh, Z., Wood, K., and Zaharijas, G.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The recent detection of extended $\gamma$-ray emission around middle-aged pulsars is interpreted as inverse-Compton scattering of ambient photons by electron-positron pairs escaping the pulsar wind nebula, which are confined near the system by unclear mechanisms. This emerging population of $\gamma$-ray sources was first discovered at TeV energies and remains underexplored in the GeV range. To address this, we conducted a systematic search for extended sources along the Galactic plane using 14 years of Fermi-LAT data above 10 GeV, aiming to identify a number of pulsar halo candidates and extend our view to lower energies. The search covered the inner Galactic plane ($\lvert l\rvert\leq$ 100$^{\circ}$, $\lvert b\rvert\leq$ 1$^{\circ}$) and the positions of known TeV sources and bright pulsars, yielding broader astrophysical interest. We found 40 such sources, forming the Second Fermi Galactic Extended Sources Catalog (2FGES), most with 68% containment radii smaller than 1.0$^{\circ}$ and relatively hard spectra with photon indices below 2.5. We assessed detection robustness using field-specific alternative interstellar emission models and by inspecting significance maps. Noting 13 sources previously known as extended in the 4FGL-DR3 catalog and five dubious sources from complex regions, we report 22 newly detected extended sources above 10 GeV. Of these, 13 coincide with H.E.S.S., HAWC, or LHAASO sources; six coincide with bright pulsars (including four also coincident with TeV sources); six are associated with 4FGL point sources only; and one has no association in the scanned catalogs. Notably, six to eight sources may be related to pulsars as classical pulsar wind nebulae or pulsar halos., Comment: 43 pages, 17 figures, 11 tables

Published
2024

3. High-resolution three-dimensional imaging of topological textures in single-diamond networks

Author

Karpov, Dmitry, Djeghdi, Kenza, Holler, Mirko, Abdollahi, S. Narjes, Godlewska, Karolina, Donnelly, Claire, Yuasa, Takeshi, Sai, Hiroaki, Wiesner, Ulrich B., Wilts, Bodo D., Steiner, Ullrich, Musya, Michimasa, Fukami, Shunsuke, Ohno, Hideo, Gunkel, Ilja, Diaz, Ana, and Llandro, Justin

Subjects
Condensed Matter - Soft Condensed Matter, Condensed Matter - Materials Science
Abstract

Highly periodic structures are often said to convey the beauty of nature. However, most material properties are strongly influenced by the defects they contain. On the mesoscopic scale, molecular self-assembly exemplifies this interplay; thermodynamic principles determine short-range order, but long-range order is mainly impeded by the kinetic history of the material and by thermal fluctuations. For the development of self-assembly technologies, it is imperative to characterise and understand the interplay between self-assembled order and defect-induced disorder. Here we used synchrotron-based hard X-ray nanotomography to reveal a pair of extended topological defects within a self-assembled single-diamond network morphology. These defects are morphologically similar to the comet and trefoil patterns of equal and opposite half-integer topological charges observed in liquid crystals and appear to maintain a constant separation across the thickness of the sample, resembling pairs of full vortices in superconductors and other hard condensed matter systems. These results are expected to open new windows to study defect formation in soft condensed matter, particularly in biological systems where most structures are formed by self-assembly., Comment: Nat. Nanotechnol. (2024)

Published
2023
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4. X-ray nanotomography reveals formation of single diamonds by block copolymer self-assembly

Author

Djeghdi, Kenza, Karpov, Dmitry, Abdollahi, S. Narjes, Godlewska, Karolina, Holler, Mirko, Donnelly, Claire, Yuasa, Takeshi, Sai, Hiroaki, Wiesner, Ulrich B., Steiner, Ullrich, Wilts, Bodo D., Musya, Michimasa, Fukami, Shunsuke, Ohno, Hideo, Diaz, Ana, Llandro, Justin, and Gunkel, Ilja

Subjects
Condensed Matter - Soft Condensed Matter, Condensed Matter - Materials Science
Abstract

Block copolymers are recognised as a valuable platform for creating nanostructured materials with unique properties. Morphologies formed by block copolymer self-assembly can be transferred into a wide range of inorganic materials, enabling applications including energy storage and metamaterials. However, imaging of the underlying, often complex, nanostructures in large volumes has remained a challenge, limiting progress in materials development. Taking advantage of recent advances in X-ray nanotomography, we non-invasively imaged exceptionally large volumes of nanostructured soft materials at high resolution, revealing a single diamond morphology in a triblock terpolymer composite network. This morphology, which is ubiquitous in nature, has so far remained elusive in block copolymers, despite its potential to create materials with large photonic bandgaps. The discovery was made possible by the precise analysis of distortions in a large volume of the self-assembled diamond network, which are difficult to unambiguously assess using traditional characterisation tools. We anticipate that high-resolution X-ray nanotomography, which allows imaging of much larger sample volumes than electron-based tomography, will become a powerful tool for the quantitative analysis of complex nanostructures and that structures such as the triblock terpolymer-directed single diamond will enable the generation of advanced multicomponent composites with hitherto unknown property profiles., Comment: updated reference 38; added reference 40; corrected name of one author; corrected one affiliation; corrected legend in Extended Data Fig. 3

Published
2023

5. Prevalence of Meticilin - resistant Staphylococcus aureus isolated from hand and nasal of hospital health worker

Author

Ahanjan M, Abdollahi S, Abdolian H, and Mohammad Nedjad Z

Subjects
Staphylococcus aureus, Methicillin, Health worker, Medicine, Medicine (General), R5-920
Abstract

Background and Objective: Methicillin-resistant Staphylococcus aureus is a common pathogen responsible for health-care-related infections. This study was done to determine the prevalence of Meticilin - resistant Staphylococcus isolated from hand and nasal of hospital health worker. Methods: This descriptive study was conducted on 148 health workers in teaching hospitals in Sari, northern Iran during 2011-12. Samples were collected from fingers and noses and were cultured on mannitol salt agar immediately. Suspected colonies were identified using Gram staining, catalase and coagulase tests. Susceptibility testing was performed by disk diffusion method. Methicillin resistant strains were determined using micro dilution broth method. Results: Staphylococcus aureus was observed in 24 (16.2%) of individuals. 9.5% of population was resistant to Methicillin. The high portions of Staphylococcus aureus carreier were in the operation room, angiography and internal pediatric ward health worker. Methicillin Staphylococcus aureus resistanat were more common in nasal samples of the operation room personal and angiography ward health worker. All strains were sensitive to Vancomycin and Chloramphenicol and resistant to Penicillin and Amoxicillin. Conclusion: In this study the prevalence of the Staphylococcus.aureus in teaching hospitals health worker was low while Staphylococcus aureus resistant to methicillin was higher than other reports in Iran.

Published
2014

6. The Fermi-LAT Light Curve Repository

Author

Abdollahi, S., Ajello, M., Baldini, L., Ballet, J., Bastieri, D., Gonzalez, J. Becerra, Bellazzini, R., Berretta, A., Bissaldi, E., Bonino, R., Brill, A., Bruel, P., Burns, E., Buson, S., Cameron, A., Caputo, R., Caraveo, P. A., Cibrario, N., Ciprini, S., Orestano, P. Cristarella, Crnogorcevic, M., Cutini, S., D'Ammando, F., De Gaetano, S., Digel, S. W., Di Lalla, N., Di Venere, L., Domínguez, A., Ramazani, V. Fallah, Fegan, S. J., Ferrara, E. C., Fiori, A., Fleischhack, H., Franckowiak, A., Fukazawa, Y., Fusco, P., Gammaldi, V., Gargano, F., Garrappa, S., Gasbarra, C., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guiriec, S., Gustafsson, M., Hays, E., Horan, D., Hou, X., Jóhannesson, G., Kerr, M., Kocevski, D., Kuss, M., Latronico, L., Li, J., Liodakis, I., Longo, F., Loparco, F., Lorusso, L., Lott, B., Lovellette, M. N., Lubrano, P., Maldera, S., Manfreda, A., Mart\'-Devesa, G., Mazziotta, M. N., Mereu, I., Meyer, M., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Omodei, N., Orlando, E., Ormes, J. F., Paneque, D., Panzarini, G., Perkins, J. S., Persic, M., Pesce-Rollins, M., Pillera, R., Porter, T. A., Principe, G., Racusin, J. L., Rainò, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Sánchez-Conde, M., Parkinson, P. M. Saz, Scargle, Jeff, Scotton, L., Serini, D., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Thompson, D. J., Torres, D. F., Valverde, J., Venters, T., Wadiasingh, Z., Wagner, S., and Wood, K.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The Fermi Large Area Telescope (LAT) light curve repository (LCR) is a publicly available, continually updated library of gamma-ray light curves of variable Fermi-LAT sources generated over multiple timescales. The Fermi-LAT LCR aims to provide publication-quality light curves binned on timescales of 3 days, 7 days, and 30 days for 1525 sources deemed variable in the source catalog of the first 10 years of Fermi-LAT observations. The repository consists of light curves generated through full likelihood analyses that model the sources and the surrounding region, providing fluxes and photon indices for each time bin. The LCR is intended as a resource for the time-domain and multi-messenger communities by allowing users to quickly search LAT data to identify correlated variability and flaring emission episodes from gamma-ray sources. We describe the sample selection and analysis employed by the LCR and provide an overview of the associated data access portal., Comment: Accepted for publication in ApJ Supplement Series

Published
2023
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7. Search for new cosmic-ray acceleration sites within the 4FGL catalog Galactic plane sources

Author

Collaboration, Fermi-LAT, Abdollahi, S., Acero, F., Ackermann, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bellazzini, R., Berenji, B., Berretta, A., Bissaldi, E., Blandford, R. D., Bonino, R., Bruel, P., Buson, S., Cameron, R. A., Caputo, R., Caraveo, P. A., Castro, D., Chiaro, G., Cibrario, N., Ciprini, S., Coronado-Blázquez, J., Crnogorcevic, M., Cutini, S., D'Ammando, F., De Gaetano, S., Di Lalla, N., Dirirsa, F., Di Venere, L., Domínguez, A., Fegan, S. J., Fiori, A., Fleischhack, H., Franckowiak, A., Fukazawa, Y., Fusco, P., Gammaldi, V., Gargano, F., Gasparrini, D., Giacchino, F., Giglietto, N., Giordano, F., Giroletti, M., Glanzman, T., Green, D., Grenier, I. A., Grondin, M. -H., Guiriec, S., Gustafsson, M., Harding, A. K., Hays, E., Hewitt, J. W., Horan, D., Hou, X., Jóhannesson, G., Kayanoki, T., Kerr, M., Kuss, M., Larsson, S., Latronico, L., Lemoine-Goumard, M., Li, J., Longo, F., Loparco, F., Lubrano, P., Maldera, S., Malyshev, D., Manfreda, A., Martí-Devesa, G., Mazziotta, M. N., Mereu, I., Michelson, P. F., Mirabal, N., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Nuss, E., Omodei, N., Orienti, M., Orlando, E., Ormes, J. F., Paneque, D., Pei, Z., Persic, M., Pesce-Rollins, M., Pillera, R., Poon, H., Porter, T. A., Principe, G., Rainò, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Reposeur, T., Sánchez-Conde, M., Parkinson, P. M. Saz, Scotton, L., Serini, D., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Sueoka, K., Suson, D. J., Tajima, H., Tak, D., Thayer, J. B., Torres, D. F., Troja, E., Valverde, J., Wadiasingh, Z., Wood, K., and Zaharijas, G.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Cosmic rays are mostly composed of protons accelerated to relativistic speeds. When those protons encounter interstellar material, they produce neutral pions which in turn decay into gamma rays. This offers a compelling way to identify the acceleration sites of protons. A characteristic hadronic spectrum, with a low-energy break around 200 MeV, was detected in the gamma-ray spectra of four Supernova Remnants (SNRs), IC 443, W44, W49B and W51C, with the Fermi Large Area Telescope. This detection provided direct evidence that cosmic-ray protons are (re-)accelerated in SNRs. Here, we present a comprehensive search for low-energy spectral breaks among 311 4FGL catalog sources located within 5 degrees from the Galactic plane. Using 8 years of data from the Fermi Large Area Telescope between 50 MeV and 1 GeV, we find and present the spectral characteristics of 56 sources with a spectral break confirmed by a thorough study of systematic uncertainty. Our population of sources includes 13 SNRs for which the proton-proton interaction is enhanced by the dense target material; the high-mass gamma-ray binary LS~I +61 303; the colliding wind binary eta Carinae; and the Cygnus star-forming region. This analysis better constrains the origin of the gamma-ray emission and enlarges our view to potential new cosmic-ray acceleration sites., Comment: Accepted for publication in The Astrophysical Journal

Published
2022
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9. Study of the Cosmic Rays and Interstellar Medium in Local HI Clouds using Fermi-LAT Gamma-Ray Observations

Author

Mizuno, T., Abdollahi, S., Fukui, Y., Hayashi, K., Koyama, T., Okumura, A., Tajima, H., and Yamamoto, H.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

An accurate estimate of the interstellar gas density distribution is crucial to understanding the interstellar medium (ISM) and Galactic cosmic rays (CRs). To comprehend the ISM and CRs in a local environment, a study of the diffuse $\gamma$-ray emission in a mid-latitude region of the third quadrant was performed. The $\gamma$-ray data in the 0.1--25.6~GeV energy range of the Fermi Large Area Telescope (LAT) and other interstellar gas tracers such as the HI4PI survey data and the Planck dust thermal emission model were used, and the northern and southern regions were analyzed separately. The variation of the dust emission Dem with the total neutral gas column density NH was studied in high dust-temperature areas, and the NH/Dem ratio was calibrated using $\gamma$-ray data under the assumption of a uniform CR intensity in the studied regions. The measured integrated $\gamma$-ray emissivities above 100~MeV are $(1.58\pm0.04)\times10^{-26}~\mathrm{photons~s^{-1}~sr^{-1}~H\mbox{-}atom^{-1}}$ and $(1.59\pm0.02)\times10^{-26}~\mathrm{photons~s^{-1}~sr^{-1}~H\mbox{-}atom^{-1}}$ in the northern and southern regions, respectively, supporting the existence of a uniform CR intensity in the vicinity of the solar system. While most of the gas can be interpreted to be HI with a spin temperature of $T_\mathrm{S} = 125~\mathrm{K}$ or higher, an area dominated by optically thick HI with $T_\mathrm{S} \sim 40~\mathrm{K}$ was identified., Comment: accepted for publication in ApJ

Published
2020
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11. VERITAS and Fermi-LAT observations of new HAWC sources

Author

VERITAS Collaboration, Abeysekara, A. U., Archer, A., Benbow, W., Bird, R., Brose, R., Buchovecky, M., Buckley, J. H., Bugaev, V., Chromey, A. J., Connolly, M. P., Cui, W., Daniel, M. K., Falcone, A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Hutten, M., Hanna, D., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Johnson, C. A., Kaaret, P., Kar, P., Kertzman, M., Kieda, D., Krause, M., Krennrich, F., Kumar, S., Lang, M. J., Lin, T. T. Y., McArthur, S., Moriarty, P., Mukherjee, R., O'Brien, S., Ong, R. A., Otte, A. N., Park, N., Petrashyk, A., Pohl, M., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Richards, G. T., Roache, E., Rulten, C., Sadeh, I., Santander, M., Sembroski, G. H., Shahinyan, K., Sushch, I., Tyler, J., Wakely, S. P., Weinstein, A., Wells, R. M., Wilcox, P., Wilhelm, A., Williams, D. A., Williamson, T. J., Zitzer, B., Collaboration, Fermi-LAT, Abdollahi, S., Ajello, M., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Berenji, B., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, E., Brandt, T. J., Bruel, P., Buehler, R., Cameron, R. A., Caputo, R., Caraveo, P. A., Castro, D., Cavazzuti, E., Charles, E., Chiaro, G., Ciprini, S., Cohen-Tanugi, J., Costantin, D., Cutini, S., D'Ammando, F., de Palma, F., Di Lalla, N., Di Mauro, M., Di Venere, L., Dominguez, A., Favuzzi, C., Fegan, S. J., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guillemot, L., Guiriec, S., Hays, E., Hewitt, J. W., Horan, D., Johannesson, G., Kensei, S., Kuss, M., Larsson, S., Latronico, L., Lemoine-Goumard, M., Li, J., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Magill, J. D., Maldera, S., Mazziotta, M. N., McEnery, J. E., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Ojha, R., Omodei, N., Orienti, M., Orlando, E., Palatiello, M., Paliya, V. S., Paneque, D., Perkins, J. S., Persic, M., Pesce-Rollins, M., Petrosian, V., Piron, F., Porter, T. A., Principe, G., Raino, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Reposeur, T., Sgro, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Thayer, J. B., Thompson, D. J., Torres, D. F., Tosti, G., Troja, E., Valverde, J., Vianello, G., Vogel, M., Wood, K., Yassine, M., Collaboration, HAWC, Alfaro, R., Alvarez, C., Alvarez, J. D., Arceo, R., Arteaga-Velazquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Bernal, A., Braun, J., Brisbois, C., Caballero-Mora, K. S., Capistran, T., Carraminana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., de Leon, S. Coutino, De Leon, C., De la Fuente, E., Dichiara, S., Dingus, B. L., DuVernois, M. A., Diaz-Velez, J. C., Engel, K., Enriquez-Rivera, O., Fiorino, D. W., Fleischhack, H., Fraija, N., Garcia-Gonzalez, J. A., Garfias, F., Munoz, A. Gonzalez, Gonzalez, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hernandez-Almada, A., Hona, B., Hueyotl-Zahuantitla, F., Hui, C. M., Huntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. Leon, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Luna-Garcia, R., Lopez-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martinez-Castro, J., Martinez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafa, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Perez-Perez, E. G., Ren, Z., Rho, C. D., Riviere, C., Rosa-Gonzalez, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Arroyo, M. Seglar, Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Villasenor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Yodh, G., Zepeda, A., and Zhou, H.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The HAWC (High Altitude Water Cherenkov) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100~GeV) gamma-ray sources based on 507 days of observation. Among these, there are nineteen sources that are not associated with previously known TeV sources. We have studied fourteen of these sources without known counterparts with VERITAS and Fermi-LAT. VERITAS detected weak gamma-ray emission in the 1~TeV-30~TeV band in the region of DA 495, a pulsar wind nebula coinciding with 2HWC J1953+294, confirming the discovery of the source by HAWC. We did not find any counterpart for the selected fourteen new HAWC sources from our analysis of Fermi-LAT data for energies higher than 10 GeV. During the search, we detected GeV gamma-ray emission coincident with a known TeV pulsar wind nebula, SNR G54.1+0.3 (VER J1930+188), and a 2HWC source, 2HWC J1930+188. The fluxes for isolated, steady sources in the 2HWC catalog are generally in good agreement with those measured by imaging atmospheric Cherenkov telescopes. However, the VERITAS fluxes for SNR G54.1+0.3, DA 495, and TeV J2032+4130 are lower than those measured by HAWC and several new HAWC sources are not detected by VERITAS. This is likely due to a change in spectral shape, source extension, or the influence of diffuse emission in the source region., Comment: Accepted for publication in the ApJ, Corresponding author: Nahee Park (VERITAS Collaboration), John W. Hewitt (Fermi-LAT Collaboration), Ignacio Taboada (HAWC Collaboration), 30 pages, 12 figures

Published
2018
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12. Cosmic-ray electron+positron spectrum from 7 GeV to 2 TeV with the Fermi Large Area Telescope

Author

Collaboration, Fermi-LAT, Abdollahi, S., Ackermann, M., Ajello, M., Atwood, W. B., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Bloom, E. D., Bonino, R., Brandt, T. J., Bregeon, J., Bruel, P., Buehler, R., Cameron, R. A., Caputo, R., Caragiulo, M., Castro, D., Cavazzuti, E., Cecchi, C., Chekhtman, A., Ciprini, S., Cohen-Tanugi, J., Costanza, F., Cuoco, A., Cutini, S., D'Ammando, F., de Palma, F., Desiante, R., Digel, S. W., Di Lalla, N., Di Mauro, M., Di Venere, L., Drell, P. S., Drlica-Wagner, A., Favuzzi, C., Focke, W. B., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Guillemot, L., Guiriec, S., Harding, A. K., Jogler, T., Jóhannesson, G., Kamae, T., Kuss, M., La Mura, G., Latronico, L., Longo, F., Loparco, F., Lubrano, P., Maldera, S., Malyshev, D., Manfreda, A., Mazziotta, M. N., Michelson, P. F., Mirabal, N., Mitthumsiri, W., Mizuno, T., Moiseev, A. A., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Orlando, E., Paneque, D., Perkins, J. S., Pesce-Rollins, M., Piron, F., Pivato, G., Porter, T. A., Principe, G., Rainò, S., Rando, R., Razzano, M., Reimer, A., Reimer, O., Sgrò, C., Simone, D., Siskind, E. J., Spada, F., Spandre, G., Spinelli, P., Tajima, H., Thayer, J. B., Tibaldo, L., Torres, D. F., Troja, E., Wood, M., Worley, A., Zaharijas, G., and Zimmer, S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present a measurement of the cosmic-ray electron+positron spectrum between 7 GeV and 2 TeV performed with almost seven years of data collected with the Fermi Large Area Telescope. We find that the spectrum is well fit by a broken power law with a break energy at about 50 GeV. Above 50 GeV, the spectrum is well described by a single power law with a spectral index of $3.07 \pm 0.02 \; (\text{stat+syst}) \pm 0.04 \; (\text{energy measurement})$. An exponential cutoff lower than 1.8 TeV is excluded at 95\% CL.

Published
2017
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17. The second catalog of flaring gamma-ray sources from the Fermi All-sky Variability Analysis

Author

Abdollahi, S., Ackermann, M., Ajello, M., Albert, A., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Gonzalez, J. Becerra, Bellazzini, R., Bissaldi, E., Blandford, R. D., Bloom, E. D., Bonino, R., Bottacini, E., Bregeon, J., Bruel, P., Buehler, R., Buson, S., Cameron, R. A., Caragiulo, M., Caraveo, P. A., Cavazzuti, E., Cecchi, C., Chekhtman, A., Cheung, C. C., Chiaro, G., Ciprini, S., Conrad, J., Costantin, D., Costanza, F., Cutini, S., D'Ammando, F., de Palma, F., Desai, A., Desiante, R., Digel, S. W., Di Lalla, N., Di Mauro, M., Di Venere, L., Donaggio, B., Drell, P. S., Favuzzi, C., Fegan, S. J., Ferrara, E. C., Focke, W. B., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giomi, M., Giordano, F., Giroletti, M., Glanzman, T., Green, D., Grenier, I. A., Grove, J. E., Guillemot, L., Guiriec, S., Hays, E., Horan, D., Jogler, T., Jóhannesson, G., Johnson, A. S., Kocevski, D., Kuss, M., La Mura, G., Larsson, S., Latronico, L., Li, J., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Magill, J. D., Maldera, S., Manfreda, A., Mayer, M., Mazziotta, M. N., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Ohsugi, T., Omodei, N., Orienti, M., Orlando, E., Paliya, V. S., Paneque, D., Perkins, J. S., Persic, M., Pesce-Rollins, M., Petrosian, V., Piron, F., Porter, T. A., Principe, G., Rainò, S., Rando, R., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Sgrò, C., Simone, D., Siskind, E. J., Spada, F., Spandre, G., Spinelli, P., Stawarz, L., Suson, D. J., Takahashi, M., Tanaka, K., Thayer, J. B., Thompson, D. J., Torres, D. F., Torresi, E., Tosti, G., Troja, E., Vianello, G., and Wood, K. S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present the second catalog of flaring gamma-ray sources (2FAV) detected with the Fermi All-sky Variability Analysis (FAVA), a tool that blindly searches for transients over the entire sky observed by the Large Area Telescope (LAT) on board the \textit{Fermi} Gamma-ray Space Telescope. With respect to the first FAVA catalog, this catalog benefits from a larger data set, the latest LAT data release (Pass 8), as well as from an improved analysis that includes likelihood techniques for a more precise localization of the transients. Applying this analysis on the first 7.4 years of \textit{Fermi} observations, and in two separate energy bands 0.1$-$0.8 GeV and 0.8$-$300 GeV, a total of 4547 flares has been detected with a significance greater than $6\sigma$ (before trials), on the time scale of one week. Through spatial clustering of these flares, 518 variable gamma-ray sources are identified. Likely counterparts, based on positional coincidence, have been found for 441 sources, mostly among the blazar class of active galactic nuclei. For 77 2FAV sources, no likely gamma-ray counterpart has been found. For each source in the catalog, we provide the time, location, and spectrum of each flaring episode. Studying the spectra of the flares, we observe a harder-when-brighter behavior for flares associated with blazars, with the exception of BL Lac flares detected in the low-energy band. The photon indexes of the flares are never significantly smaller than 1.5. For a leptonic model, and under the assumption of isotropy, this limit suggests that the spectrum of the freshly accelerated electrons is never harder than $p\sim$2., Comment: Accepted for publication by The Astrophysical Journal Supplement. Online analysis results available at http://fermi.gsfc.nasa.gov/ssc/data/access/lat/FAVA/index.php . Corresponding authors: M. Giomi, R. Buehler, D. Kocevski, and M. Ajello

Published
2016
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18. Quantifying the Interstellar Medium and Cosmic Rays in the MBM 53, 54, and 55 Molecular Clouds and the Pegasus Loop using Fermi-LAT Gamma-ray Observations

Author

Mizuno, T., Abdollahi, S., Fukui, Y., Hayashi, K., Okumura, A., Tajima, H., and Yamamoto, H.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

A study of the interstellar medium (ISM) and cosmic rays (CRs) using Fermi Large Area Telescope (LAT) data, in a region encompassing the nearby molecular clouds MBM 53, 54, and 55 and a far-infrared loop-like structure in Pegasus, is reported. By comparing Planck dust thermal emission model with Fermi-LAT gamma-ray data, it was found that neither the dust radiance (R) nor the dust opacity at 353 GHz (tau353) were proportional to the total gas column density N(Htot) primarily because N(Htot)/R and N(Htot)/tau353 depend on the dust temperature (Td). The N(Htot) distribution was evaluated using gamma-ray data by assuming the regions of high Td} to be dominated by optically thin atomic hydrogen (HI) and by employing an empirical linear relation of N(Htot)/R to Td. It was determined that the mass of the gas not traced by the 21-cm or 2.6-mm surveys is ~25% of the mass of HI in the optically thin case and is larger than the mass of the molecular gas traced by carbon monoxide by a factor of up to 5. The measured gamma-ray emissivity spectrum is consistent with a model based on CR spectra measured at the Earth and the nuclear enhancement factor of <=1.5. It is, however, lower than local HI emissivities reported by previous Fermi-LAT studies employing different analysis methods and assumptions on ISM properties by 15%-20% in energies below a few GeV, even if we take account of the statistical and systematic uncertainties. The origin of the discrepancy is also discussed., Comment: accepted for publication in ApJ

Published
2016
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20. The Third Fermi Large Area Telescope Catalog of Gamma-Ray Pulsars

Author

Smith, D. A., primary, Abdollahi, S., additional, Ajello, M., additional, Bailes, M., additional, Baldini, L., additional, Ballet, J., additional, Baring, M. G., additional, Bassa, C., additional, Gonzalez, J. Becerra, additional, Bellazzini, R., additional, Berretta, A., additional, Bhattacharyya, B., additional, Bissaldi, E., additional, Bonino, R., additional, Bottacini, E., additional, Bregeon, J., additional, Bruel, P., additional, Burgay, M., additional, Burnett, T. H., additional, Cameron, R. A., additional, Camilo, F., additional, Caputo, R., additional, Caraveo, P. A., additional, Cavazzuti, E., additional, Chiaro, G., additional, Ciprini, S., additional, Clark, C. J., additional, Cognard, I., additional, Corongiu, A., additional, Orestano, P. Cristarella, additional, Crnogorcevic, M., additional, Cuoco, A., additional, Cutini, S., additional, D’Ammando, F., additional, de Angelis, A., additional, DeCesar, M. E., additional, De Gaetano, S., additional, de Menezes, R., additional, Deneva, J., additional, de Palma, F., additional, Di Lalla, N., additional, Dirirsa, F., additional, Di Venere, L., additional, Domínguez, A., additional, Dumora, D., additional, Fegan, S. J., additional, Ferrara, E. C., additional, Fiori, A., additional, Fleischhack, H., additional, Flynn, C., additional, Franckowiak, A., additional, Freire, P. C. C., additional, Fukazawa, Y., additional, Fusco, P., additional, Galanti, G., additional, Gammaldi, V., additional, Gargano, F., additional, Gasparrini, D., additional, Giacchino, F., additional, Giglietto, N., additional, Giordano, F., additional, Giroletti, M., additional, Green, D., additional, Grenier, I. A., additional, Guillemot, L., additional, Guiriec, S., additional, Gustafsson, M., additional, Harding, A. K., additional, Hays, E., additional, Hewitt, J. W., additional, Horan, D., additional, Hou, X., additional, Jankowski, F., additional, Johnson, R. P., additional, Johnson, T. J., additional, Johnston, S., additional, Kataoka, J., additional, Keith, M. J., additional, Kerr, M., additional, Kramer, M., additional, Kuss, M., additional, Latronico, L., additional, Lee, S.-H., additional, Li, D., additional, Li, J., additional, Limyansky, B., additional, Longo, F., additional, Loparco, F., additional, Lorusso, L., additional, Lovellette, M. N., additional, Lower, M., additional, Lubrano, P., additional, Lyne, A. G., additional, Maan, Y., additional, Maldera, S., additional, Manchester, R. N., additional, Manfreda, A., additional, Marelli, M., additional, Martí-Devesa, G., additional, Mazziotta, M. N., additional, McEnery, J. E., additional, Mereu, I., additional, Michelson, P. F., additional, Mickaliger, M., additional, Mitthumsiri, W., additional, Mizuno, T., additional, Moiseev, A. A., additional, Monzani, M. E., additional, Morselli, A., additional, Negro, M., additional, Nemmen, R., additional, Nieder, L., additional, Nuss, E., additional, Omodei, N., additional, Orienti, M., additional, Orlando, E., additional, Ormes, J. F., additional, Palatiello, M., additional, Paneque, D., additional, Panzarini, G., additional, Parthasarathy, A., additional, Persic, M., additional, Pesce-Rollins, M., additional, Pillera, R., additional, Poon, H., additional, Porter, T. A., additional, Possenti, A., additional, Principe, G., additional, Rainò, S., additional, Rando, R., additional, Ransom, S. M., additional, Ray, P. S., additional, Razzano, M., additional, Razzaque, S., additional, Reimer, A., additional, Reimer, O., additional, Renault-Tinacci, N., additional, Romani, R. W., additional, Sánchez-Conde, M., additional, Parkinson, P. M. Saz, additional, Scotton, L., additional, Serini, D., additional, Sgrò, C., additional, Shannon, R., additional, Sharma, V., additional, Shen, Z., additional, Siskind, E. J., additional, Spandre, G., additional, Spinelli, P., additional, Stappers, B. W., additional, Stephens, T. E., additional, Suson, D. J., additional, Tabassum, S., additional, Tajima, H., additional, Tak, D., additional, Theureau, G., additional, Thompson, D. J., additional, Tibolla, O., additional, Torres, D. F., additional, Valverde, J., additional, Venter, C., additional, Wadiasingh, Z., additional, Wang, N., additional, Wang, P., additional, Weltevrede, P., additional, Wood, K., additional, Yan, J., additional, Zaharijas, G., additional, Zhang, C., additional, and Zhu, W., additional

Published
2023
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25. The Fermi-LAT Lightcurve Repository

Author

Abdollahi, S., Johannesson, G., Negro, M., Valverde, J., Wood, K., Abdollahi, S., Johannesson, G., Negro, M., Valverde, J., and Wood, K.

Abstract

The Fermi Large Area Telescope (LAT) lightcurve repository (LCR) is a publicly available, continually updated library of gamma-ray lightcurves of variable Fermi-LAT sources generated over multiple timescales. The Fermi-LAT LCR aims to provide publication-quality lightcurves binned on timescales of 3, 7, and 30 days for 1525 sources deemed variable in the source catalog of the first 10 yr of Fermi-LAT observations. The repository consists of lightcurves generated through full likelihood analyses that model the sources and the surrounding region, providing fluxes and photon indices for each time bin. The LCR is intended as a resource for the time-domain and multimessenger communities by allowing users to search LAT data quickly to identify correlated variability and flaring emission episodes from gamma-ray sources. We describe the sample selection and analysis employed by the LCR and provide an overview of the associated data access portal., QC 20230529

Published
2023
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26. The Fermi-LAT Lightcurve Repository*

Author

Abdollahi, S., primary, Ajello, M., additional, Baldini, L., additional, Ballet, J., additional, Bastieri, D., additional, Becerra Gonzalez, J., additional, Bellazzini, R., additional, Berretta, A., additional, Bissaldi, E., additional, Bonino, R., additional, Brill, A., additional, Bruel, P., additional, Burns, E., additional, Buson, S., additional, Cameron, R. A., additional, Caputo, R., additional, Caraveo, P. A., additional, Cibrario, N., additional, Ciprini, S., additional, Cristarella Orestano, P., additional, Crnogorcevic, M., additional, Cutini, S., additional, D’Ammando, F., additional, De Gaetano, S., additional, Digel, S. W., additional, Di Lalla, N., additional, Di Venere, L., additional, Domínguez, A., additional, Ramazani, V. Fallah, additional, Fegan, S. J., additional, Ferrara, E. C., additional, Fiori, A., additional, Fleischhack, H., additional, Franckowiak, A., additional, Fukazawa, Y., additional, Fusco, P., additional, Gammaldi, V., additional, Gargano, F., additional, Garrappa, S., additional, Gasbarra, C., additional, Gasparrini, D., additional, Giglietto, N., additional, Giordano, F., additional, Giroletti, M., additional, Green, D., additional, Grenier, I. A., additional, Guiriec, S., additional, Gustafsson, M., additional, Hays, E., additional, Horan, D., additional, Hou, X., additional, Jóhannesson, G., additional, Kerr, M., additional, Kocevski, D., additional, Kuss, M., additional, Latronico, L., additional, Li, J., additional, Liodakis, I., additional, Longo, F., additional, Loparco, F., additional, Lorusso, L., additional, Lott, B., additional, Lovellette, M. N., additional, Lubrano, P., additional, Maldera, S., additional, Manfreda, A., additional, Martí-Devesa, G., additional, Mazziotta, M. N., additional, Mereu, I., additional, Meyer, M., additional, Michelson, P. F., additional, Mizuno, T., additional, Monzani, M. E., additional, Morselli, A., additional, Moskalenko, I. V., additional, Negro, M., additional, Omodei, N., additional, Orlando, E., additional, Ormes, J. F., additional, Paneque, D., additional, Panzarini, G., additional, Perkins, J. S., additional, Persic, M., additional, Pesce-Rollins, M., additional, Pillera, R., additional, Porter, T. A., additional, Principe, G., additional, Racusin, J. L., additional, Rainò, S., additional, Rando, R., additional, Rani, B., additional, Razzano, M., additional, Razzaque, S., additional, Reimer, A., additional, Reimer, O., additional, Sánchez-Conde, M., additional, Parkinson, P. M. Saz, additional, Scargle, Jeff, additional, Scotton, L., additional, Serini, D., additional, Sgrò, C., additional, Siskind, E. J., additional, Spandre, G., additional, Spinelli, P., additional, Suson, D. J., additional, Tajima, H., additional, Thompson, D. J., additional, Torres, D. F., additional, Valverde, J., additional, Venters, T., additional, Wadiasingh, Z., additional, Wagner, S., additional, and Wood, K., additional

Published
2023
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28. Design of a Synchronous Reluctance Motor with New Hybrid Lamination Rotor Structure.

Author

Rouhani, R., Abdollahi, S. E., and Gholamian, S. A.

Subjects
SYNCHRONOUS electric motors, MAGNETIC circuits, TORQUE, KINEMATICS, CONCEPTUAL design
Abstract

Background and Objectives: The rotor of synchronous reluctance machines (SynRM) is conventionally designed and implemented in two types of axiallylaminated anisotropic (ALA) and transversely-laminated anisotropic (TLA). Torque ripple and power factor have always been the design challenges of this machine; however, with proper design, their values can be as close as possible to the desired value. Each of these two structures has some advantages over the other, in terms of electromagnetic performance and ease of construction. For the first time, in this paper, a hybrid anisotropic rotor is presented with both radial and axial laminations, based on the theory of anisotropic rotor structure for the fundamental harmonic and isotropic rotor structure for other harmonics, so that the designed motor meets the advantages of both structures as much as possible. Methods: To this end, the proposed design is implemented and investigated a Magnetic Equivalent Circuit (MEC) for the first slot harmonic on a machine with stator of 24-slots. To evaluate the proposed design, its electromagnetic performance is simulated using Finite Element Method. Results: The theory-based conceptual design method is applied to a rotor with new structure and simulation results including average torque, power factor and torque ripple of the machine are presented. Conclusion: Based on the obtained simulation results and comparing performance of the proposed design with other structures, it is shown that there will be a significant improvement in electromagnetic features including torque ripple, average torque and power factor and the proposed design has lower torque ripple than ALA rotor and higher average torque and power factor than TLA rotor. [ABSTRACT FROM AUTHOR]

Published
2023
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30. Search for New Cosmic-Ray Acceleration Sites within the 4FGL Catalog Galactic Plane Sources

Author

Abdollahi, S., primary, Acero, F., additional, Ackermann, M., additional, Baldini, L., additional, Ballet, J., additional, Barbiellini, G., additional, Bastieri, D., additional, Bellazzini, R., additional, Berenji, B., additional, Berretta, A., additional, Bissaldi, E., additional, Blandford, R. D., additional, Bonino, R., additional, Bruel, P., additional, Buson, S., additional, Cameron, R. A., additional, Caputo, R., additional, Caraveo, P. A., additional, Castro, D., additional, Chiaro, G., additional, Cibrario, N., additional, Ciprini, S., additional, Coronado-Blázquez, J., additional, Crnogorcevic, M., additional, Cutini, S., additional, D’Ammando, F., additional, De Gaetano, S., additional, Di Lalla, N., additional, Dirirsa, F., additional, Di Venere, L., additional, Domínguez, A., additional, Fegan, S. J., additional, Fiori, A., additional, Fleischhack, H., additional, Franckowiak, A., additional, Fukazawa, Y., additional, Fusco, P., additional, Gammaldi, V., additional, Gargano, F., additional, Gasparrini, D., additional, Giacchino, F., additional, Giglietto, N., additional, Giordano, F., additional, Giroletti, M., additional, Glanzman, T., additional, Green, D., additional, Grenier, I. A., additional, Grondin, M.-H., additional, Guiriec, S., additional, Gustafsson, M., additional, Harding, A. K., additional, Hays, E., additional, Hewitt, J. W., additional, Horan, D., additional, Hou, X., additional, Jóhannesson, G., additional, Kayanoki, T., additional, Kerr, M., additional, Kuss, M., additional, Larsson, S., additional, Latronico, L., additional, Lemoine-Goumard, M., additional, Li, J., additional, Longo, F., additional, Loparco, F., additional, Lubrano, P., additional, Maldera, S., additional, Malyshev, D., additional, Manfreda, A., additional, Martí-Devesa, G., additional, Mazziotta, M. N., additional, Mereu, I., additional, Michelson, P. F., additional, Mirabal, N., additional, Mitthumsiri, W., additional, Mizuno, T., additional, Monzani, M. E., additional, Morselli, A., additional, Moskalenko, I. V., additional, Nuss, E., additional, Omodei, N., additional, Orienti, M., additional, Orlando, E., additional, Ormes, J. F., additional, Paneque, D., additional, Pei, Z., additional, Persic, M., additional, Pesce-Rollins, M., additional, Pillera, R., additional, Poon, H., additional, Porter, T. A., additional, Principe, G., additional, Rainò, S., additional, Rando, R., additional, Rani, B., additional, Razzano, M., additional, Razzaque, S., additional, Reimer, A., additional, Reimer, O., additional, Reposeur, T., additional, Sánchez-Conde, M., additional, Saz Parkinson, P. M., additional, Scotton, L., additional, Serini, D., additional, Sgrò, C., additional, Siskind, E. J., additional, Spandre, G., additional, Spinelli, P., additional, Sueoka, K., additional, Suson, D. J., additional, Tajima, H., additional, Tak, D., additional, Thayer, J. B., additional, Torres, D. F., additional, Troja, E., additional, Valverde, J., additional, Wadiasingh, Z., additional, Wood, K., additional, and Zaharijas, G., additional

Published
2022
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32. Incremental Fermi Large Area Telescope Fourth Source Catalog

Author

Abdollahi, S., Acero, F., Baldini, L., Ballet, J., Bastieri, D., Bellazzini, R., Berenji, B., Berretta, A., Larsson, Stefan, Zaharijas, G., Abdollahi, S., Acero, F., Baldini, L., Ballet, J., Bastieri, D., Bellazzini, R., Berenji, B., Berretta, A., Larsson, Stefan, and Zaharijas, G.

Abstract

We present an incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi Large Area Telescope (LAT) catalog of 3-ray sources. Based on the first 12 years of science data in the energy range from 50 MeV to 1 TeV, it contains 6658 sources. The analysis improves on that used for the 4FGL catalog over eight years of data: more sources are fit with curved spectra, we introduce a more robust spectral parameterization for pulsars, and we extend the spectral points to 1 TeV. The spectral parameters, spectral energy distributions, and associations are updated for all sources. Light curves are rebuilt for all sources with 1 yr intervals (not 2 month intervals). Among the 5064 original 4FGL sources, 16 were deleted, 112 are formally below the detection threshold over 12 yr (but are kept in the list), while 74 are newly associated, 10 have an improved association, and seven associations were withdrawn. Pulsars are split explicitly between young and millisecond pulsars. Pulsars and binaries newly detected in LAT sources, as well as more than 100 newly classified blazars, are reported. We add three extended sources and 1607 new point sources, mostly just above the detection threshold, among which eight are considered identified, and 699 have a plausible counterpart at other wavelengths. We discuss the degree-scale residuals to the global sky model and clusters of soft unassociated point sources close to the Galactic plane, which are possibly related to limitations of the interstellar emission model and missing extended sources. © 2022. The Author(s). Published by the American Astronomical Society.

Published
2022
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33. Search for New Cosmic-Ray Acceleration Sites within the 4FGL Catalog Galactic Plane Sources

Author

Abdollahi, S., Ballet, J., Johannesson, G., Larsson, Stefan, Zaharijas, G., Abdollahi, S., Ballet, J., Johannesson, G., Larsson, Stefan, and Zaharijas, G.

Abstract

Cosmic rays are mostly composed of protons accelerated to relativistic speeds. When those protons encounter interstellar material, they produce neutral pions, which in turn decay into gamma-rays. This offers a compelling way to identify the acceleration sites of protons. A characteristic hadronic spectrum, with a low-energy break around 200 MeV, was detected in the gamma-ray spectra of four supernova remnants (SNRs), IC 443, W44, W49B, and W51C, with the Fermi Large Area Telescope. This detection provided direct evidence that cosmic-ray protons are (re-)accelerated in SNRs. Here, we present a comprehensive search for low-energy spectral breaks among 311 4FGL catalog sources located within 5 degrees from the Galactic plane. Using 8 yr of data from the Fermi Large Area Telescope between 50 MeV and 1 GeV, we find and present the spectral characteristics of 56 sources with a spectral break confirmed by a thorough study of systematic uncertainty. Our population of sources includes 13 SNRs for which the proton-proton interaction is enhanced by the dense target material; the high-mass gamma-ray binary LS I+61 303; the colliding wind binary eta Carinae; and the Cygnus star-forming region. This analysis better constrains the origin of the gamma-ray emission and enlarges our view to potential new cosmic-ray acceleration sites., QC 20220728

Published
2022
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37. Incremental Fermi Large Area Telescope Fourth Source Catalog

Author

Abdollahi, S., primary, Acero, F., additional, Baldini, L., additional, Ballet, J., additional, Bastieri, D., additional, Bellazzini, R., additional, Berenji, B., additional, Berretta, A., additional, Bissaldi, E., additional, Blandford, R. D., additional, Bloom, E., additional, Bonino, R., additional, Brill, A., additional, Britto, R. J., additional, Bruel, P., additional, Burnett, T. H., additional, Buson, S., additional, Cameron, R. A., additional, Caputo, R., additional, Caraveo, P. A., additional, Castro, D., additional, Chaty, S., additional, Cheung, C. C., additional, Chiaro, G., additional, Cibrario, N., additional, Ciprini, S., additional, Coronado-Blázquez, J., additional, Crnogorcevic, M., additional, Cutini, S., additional, D’Ammando, F., additional, De Gaetano, S., additional, Digel, S. W., additional, Di Lalla, N., additional, Dirirsa, F., additional, Di Venere, L., additional, Domínguez, A., additional, Fallah Ramazani, V., additional, Fegan, S. J., additional, Ferrara, E. C., additional, Fiori, A., additional, Fleischhack, H., additional, Franckowiak, A., additional, Fukazawa, Y., additional, Funk, S., additional, Fusco, P., additional, Galanti, G., additional, Gammaldi, V., additional, Gargano, F., additional, Garrappa, S., additional, Gasparrini, D., additional, Giacchino, F., additional, Giglietto, N., additional, Giordano, F., additional, Giroletti, M., additional, Glanzman, T., additional, Green, D., additional, Grenier, I. A., additional, Grondin, M.-H., additional, Guillemot, L., additional, Guiriec, S., additional, Gustafsson, M., additional, Harding, A. K., additional, Hays, E., additional, Hewitt, J. W., additional, Horan, D., additional, Hou, X., additional, Jóhannesson, G., additional, Karwin, C., additional, Kayanoki, T., additional, Kerr, M., additional, Kuss, M., additional, Landriu, D., additional, Larsson, S., additional, Latronico, L., additional, Lemoine-Goumard, M., additional, Li, J., additional, Liodakis, I., additional, Longo, F., additional, Loparco, F., additional, Lott, B., additional, Lubrano, P., additional, Maldera, S., additional, Malyshev, D., additional, Manfreda, A., additional, Martí-Devesa, G., additional, Mazziotta, M. N., additional, Mereu, I., additional, Meyer, M., additional, Michelson, P. F., additional, Mirabal, N., additional, Mitthumsiri, W., additional, Mizuno, T., additional, Moiseev, A. A., additional, Monzani, M. E., additional, Morselli, A., additional, Moskalenko, I. V., additional, Negro, M., additional, Nuss, E., additional, Omodei, N., additional, Orienti, M., additional, Orlando, E., additional, Paneque, D., additional, Pei, Z., additional, Perkins, J. S., additional, Persic, M., additional, Pesce-Rollins, M., additional, Petrosian, V., additional, Pillera, R., additional, Poon, H., additional, Porter, T. A., additional, Principe, G., additional, Rainò, S., additional, Rando, R., additional, Rani, B., additional, Razzano, M., additional, Razzaque, S., additional, Reimer, A., additional, Reimer, O., additional, Reposeur, T., additional, Sánchez-Conde, M., additional, Saz Parkinson, P. M., additional, Scotton, L., additional, Serini, D., additional, Sgrò, C., additional, Siskind, E. J., additional, Smith, D. A., additional, Spandre, G., additional, Spinelli, P., additional, Sueoka, K., additional, Suson, D. J., additional, Tajima, H., additional, Tak, D., additional, Thayer, J. B., additional, Thompson, D. J., additional, Torres, D. F., additional, Troja, E., additional, Valverde, J., additional, Wood, K., additional, and Zaharijas, G., additional

Published
2022
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38. Psychometric Properties of Persian Version of Prenatal Health Behaviors

Author

Abdollahi, S, Faramarzi, M, Gholinia, H, and Esfandiari, M

Subjects
health behaviors, psychometrics, Medicine (General), R5-920, validation study, iran, Medicine, pregnancy
Abstract

BACKGROUND AND OBJECTIVE: Health behaviors, includes physical activity, nutrition, spiritual growth, responsibility, interpersonal relationships, and stress management. Since there is no specific tool for measuring the health behaviors of Iranian pregnant women, this study was conducted for the first time in the Iranian population in order to psychoanalyze the Persian scale of prenatal health behaviors scale. METHODS: This cross-sectional psychometric study was performed on 200 pregnant women in Babol and Amol pregnancy clinics by available sampling method. During the pregnancy care visit, women with a gestational age of 14 weeks or more completed demographic questionnaires and pregnancy health behaviors with a score range of 0-48. Scale psychometrics were performed using Cronbach's alpha and internal consistency obtained from retesting, exploratory and confirmatory factor analysis and with Amos software. FINDINGS: The mean health-promoting behaviors of pregnant women were 24.8±5.5 and destructive health behaviors were 23.7±14.2. The results of factor analysis showed that this scale in Iranian pregnant women has four domains of behavioral habits / destructive health nutrition, behavioral habits / health promoting nutrition, physical health promoting activities, destructive physical health habits with explained variance of 65.13%. Intra-cluster correlation index in all four areas of the questionnaire and also the total score of the test was above 0.9, which confirms the repeatability of this test. CONCLUSION: According to the results of this study, the Persian scale of pregnancy health behaviors has a validity and reliability to assess the health and destructive behaviors of pregnant women in Iranian society and can be used in clinical and research situations.

Published
2020

41. Carbon-Assisted Stable Silver Nanostructures

Author

Abdollahi, S. Narjes, Ochoa-Martinez, Efrain, Kilchoer, Cédric, Kremer, Geoffroy, Jaouen, Thomas, Hellmann, Tim, Mayer, Thomas, Gu, Yibei, Wiesner, Ulrich B., Steiner, Ullrich, Wilts, Bodo D., and Gunkel, Ilja

Abstract

Galley proofs for the paper Carbon-Assisted Stable Silver Nanostructures

Published
2020

42. Fermi Large Area Telescope Fourth Source Catalog

Author

Abdollahi, S.

Abstract

S. Abdollahi, F. Acero,. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, A. Berretta, E. Bissaldi, R. D. Blandford, E. D. Bloom, R. Bonino, E. Bottacini, T. J. Brandt, J. Bregeon, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, R. A. Cameron, R. Caputo, P. A. Caraveo, J. M. Casandjian, D. Castro, E. Cavazzuti, E. Charles, S. Chaty, S. Chen, C. C. Cheung, G. Chiaro, S. Ciprini, J. Cohen-Tanugi, L. R. Cominsky, J. Coronado-Blázquez, D. Costantin, A. Cuoco, S. Cutini, F. D'Ammando, M. DeKlotz, P. de la Torre Luque, F. de Palma, A. Desai, S. W. Digel, N. Di Lalla, M. Di Mauro, L. Di Venere, A. Domínguez, D. Dumora, F. Fana Dirirsa, S. J. Fegan, E. C. Ferrara, A. Franckowiak, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, D. Green, I. A. Grenier, S. Griffin, M.-H. Grondin, J. E. Grove, S. Guiriec, A. K. Harding, K. Hayashi, E. Hays, J. W. Hewitt, D. Horan, G. Jóhannesson, T. J. Johnson, T. Kamae, M. Kerr, D. Kocevski, M. Kovac'evic', M. Kuss, D. Landriu, S. Larsson, L. Latronico, M. Lemoine-Goumard, J. Li, I. Liodakis, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, S. Maldera, D. Malyshev, A. Manfreda, E. J. Marchesini, L. Marcotulli, G. Martí-Devesa, P. Martin, F. Massaro, M. N. Mazziotta, J. E. McEnery, I. Mereu, M. Meyer, P. F. Michelson20, N. Mirabal, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, E. Nuss, R. Ojha, N. Omodei, M. Orienti, E. Orlando, J. F. Ormes, M. Palatiello, V. S. Paliya, D. Paneque, Z. Pei, H. Peña-Herazo, J. S. Perkins, M. Persic, M. Pesce-Rollins, V. Petrosian, L. Petrov, F. Piron, H. Poon, T. A. Porter, G. Principe, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, Q. Remy, T. Reposeur, R. W. Romani, P. M. Saz Parkinson, F. K. Schinzel, D. Serini, C. Sgrò, E. J. Siskind, D. A. Smith, G. Spandre, P. Spinelli, A. W. Strong, D. J. Suson, H. Tajima, M. N. Takahashi, D. Tak, J. B. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, E. Torresi, J. Valverde, B. Van Klaveren, P. van Zyl, K. Wood, M. Yassine, and G. Zaharijas, We present the fourth Fermi Large Area Telescope catalog (4FGL) of γ-ray sources. Based on the first eight years of science data from the Fermi Gamma-ray Space Telescope mission in the energy range from 50 MeV to 1 TeV, it is the deepest yet in this energy range. Relative to the 3FGL catalog, the 4FGL catalog has twice as much exposure as well as a number of analysis improvements, including an updated model for the Galactic diffuse γ-ray emission, and two sets of light curves (one-year and two-month intervals). The 4FGL catalog includes 5064 sources above 4σ significance, for which we provide localization and spectral properties. Seventy-five sources are modeled explicitly as spatially extended, and overall, 358 sources are considered as identified based on angular extent, periodicity, or correlated variability observed at other wavelengths. For 1336 sources, we have not found plausible counterparts at other wavelengths. More than 3130 of the identified or associated sources are active galaxies of the blazar class, and 239 are pulsars.

Published
2020
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44. Search for Cosmic-Ray Electron and Positron Anisotropies with Seven Years of Fermi Large Area Telescope Data

Author

Abdollahi, S., Ackermann, Markus, Bonino, R., Bottacini, E., Brandt, T. J., Bruel, P., Buson, S., Caragiulo, M., Cavazzuti, E., Chekhtman, A., Ciprini, S., Costanza, Francesco, Ajello, M., Cuoco, A., Cutini, S., D’Ammando, F., de Palma, F., Desiante, R., Digel, S. W., Di Lalla, N., Di Mauro, M., Di Venere, L., Donaggio, B., Albert, A., Drell, P. S., Favuzzi, C., Focke, W. B., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Atwood, W. B., Giroletti, M., Green, D., Guiriec, S., Harding, A. K., Jogler, T., Jóhannesson, G., Kamae, T., Kuss, M., Larsson, S., Latronico, L., Baldini, L., Li, J., Longo, F., Loparco, F., Lubrano, P., Magill, J. D., Malyshev, D., Manfreda, A., Mazziotta, M. N., Meehan, M., Michelson, P. F., Barbiellini, G., Mitthumsiri, W., Mizuno, T., Moiseev, A. A., Monzani, M. E., Morselli, A., Negro, M., Nuss, E., Ohsugi, T., Omodei, N., Paneque, D., Bellazzini, R., Perkins, J. S., Pesce-Rollins, M., Piron, F., Pivato, G., Principe, G., Rainò, S., Rando, R., Razzano, M., Reimer, A., Reimer, O., Bissaldi, E., Sgrò, C., Simone, D., Siskind, E. J., Spada, F., Spandre, G., Spinelli, P., Strong, A. W., Tajima, H., Thayer, J. B., Torres, D. F., Bloom, E. D., Troja, E., Vandenbroucke, J., Zaharijas, G., Zimmer, S., Fermi-LAT Collaboration, 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), 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), Fermi-LAT, 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 ), 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 ), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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), Abdollahi S, Ackermann M, Ajello M, Albert A, Atwood WB, Baldini L, Barbiellini G, Bellazzini R, Bissaldi E, Bloom ED, Bonino R, Bottacini E, Brandt TJ, Bruel P, Buson S, Caragiulo M, Cavazzuti E, Chekhtman A, Ciprini S, Costanza F, Cuoco A, Cutini S, DAmmando F, De Palma F, Desiante R, Digel SW, Di Lalla N, Di Mauro M, Di Venere L, Donaggio B, Drell PS, Favuzzi C, Focke WB, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Giglietto N, Giordano F, Giroletti M, Green D, Guiriec S, Harding AK, Jogler T, Jóhannesson G, Kamae T, Kuss M, Larsson S, Latronico L, Li J, Longo F, Loparco F, Lubrano P, Magill JD, Malyshev D, Manfreda A, Mazziotta MN, Meehan M, Michelson PF, Mitthumsiri W, Mizuno T, Moiseev AA, Monzani ME, Morselli A, Negro M, Nuss E, Ohsugi T, Omodei N, Paneque D, Perkins JS, Pesce-Rollins M, Piron F, Pivato G, Principe G, Rainò S, Rando R, Razzano M, Reimer A, Reimer O, Sgrò C, Simone D, Siskind EJ, Spada F, Spandre G, Spinelli P, Strong AW, Tajima H, Thayer JB, Torres DF, Troja E, Vandenbroucke J, Zaharijas G, Zimmer S, Abdollahi, S, Ackermann, M., Ajello, M., Albert, A., Atwood, W. B., Baldini, L., Barbiellini, G., Bellazzini, R., Bissaldi, E., Bloom, E. D., Bonino, R., Bottacini, E., Brandt, T. J., Bruel, P., Buson, S., Caragiulo, M., Cavazzuti, E., Chekhtman, A., Ciprini, S., Costanza, F., Cuoco, A., Cutini, S., D'Ammando, F., De Palma, F., Desiante, R., Digel, S. W., Di Lalla, N., Di Mauro, M., Di Venere, L., Donaggio, B., Drell, P. S., Favuzzi, C., Focke, W. B., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Guiriec, S., Harding, A. K., Jogler, T., Jóhannesson, G., Kamae, T., Kuss, M., Larsson, S., Latronico, L., Li, J., Longo, Francesco, Loparco, F., Lubrano, P., Magill, J. D., Malyshev, D., Manfreda, A., Mazziotta, M. N., Meehan, M., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Moiseev, A. A., Monzani, M. E., Morselli, A., Negro, M., Nuss, E., Ohsugi, T., Omodei, N., Paneque, D., Perkins, J. S., Pesce Rollins, M., Piron, F., Pivato, G., Principe, G., Rainò, S., Rando, R., Razzano, M., Reimer, A., Reimer, O., Sgrò, C., Simone, D., Siskind, E. J., Spada, F., Spandre, G., Spinelli, P., Strong, A. W., Tajima, H., Thayer, J. B., Torres, D. F., Troja, E., Vandenbroucke, J., Zaharijas, G., and Zimmer, S.

Subjects
[ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, Cosmic ray, Electrons, Astrophysics, Electron, 7. Clean energy, 01 natural sciences, GLAST, law.invention, Physics and Astronomy, Cosmic rays, Anisotropy, Telescope, Physics and Astronomy (all), Positron, Spitzer Space Telescope, law, 0103 physical sciences, ddc:550, 010303 astronomy & astrophysics, Physics, potential: anisotropy, 010308 nuclear & particles physics, electron: cosmic radiation, Astronomy, Dipole anisotropy, Dipole, anisotropy: dipole, positron, Cosmic-Ray Electron and Positron Anisotropies, Fermi-LAT, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], upper limit, signature, Fermi Gamma-ray Space Telescope
Abstract

Physical review letters 118(9), 091103(2017). doi:10.1103/PhysRevLett.118.091103, The Large Area Telescope on board the Fermi Gamma-ray Space Telescope has collected the largest ever sample of high-energy cosmic-ray electron and positron events since the beginning of its operation. Potential anisotropies in the arrival directions of cosmic-ray electrons or positrons could be a signature of the presence of nearby sources. We use almost seven years of data with energies above 42 GeV processed with the Pass 8 reconstruction. The present data sample can probe dipole anisotropies down to a level of 10$^{−3}$. We take into account systematic effects that could mimic true anisotropies at this level. We present a detailed study of the event selection optimization of the cosmic-ray electrons and positrons to be used for anisotropy searches. Since no significant anisotropies have been detected on any angular scale, we present upper limits on the dipole anisotropy. The present constraints are among the strongest to date probing the presence of nearby young and middle-aged sources., Published by APS, College Park, Md.

Published
2017
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46. Carbon‐Assisted Stable Silver Nanostructures

Author

Abdollahi, S. Narjes, primary, Ochoa Martínez, Efraín, additional, Kilchoer, Cédric, additional, Kremer, Geoffroy, additional, Jaouen, Thomas, additional, Aebi, Philipp, additional, Hellmann, Tim, additional, Mayer, Thomas, additional, Gu, Yibei, additional, Wiesner, Ulrich B., additional, Steiner, Ullrich, additional, Wilts, Bodo D., additional, and Gunkel, Ilja, additional

Published
2020
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48. Fermi Large Area Telescope Fourth Source Catalog

Author

Abdollahi, S., primary, Acero, F., additional, Ackermann, M., additional, Ajello, M., additional, Atwood, W. B., additional, Axelsson, M., additional, Baldini, L., additional, Ballet, J., additional, Barbiellini, G., additional, Bastieri, D., additional, Becerra Gonzalez, J., additional, Bellazzini, R., additional, Berretta, A., additional, Bissaldi, E., additional, Blandford, R. D., additional, Bloom, E. D., additional, Bonino, R., additional, Bottacini, E., additional, Brandt, T. J., additional, Bregeon, J., additional, Bruel, P., additional, Buehler, R., additional, Burnett, T. H., additional, Buson, S., additional, Cameron, R. A., additional, Caputo, R., additional, Caraveo, P. A., additional, Casandjian, J. M., additional, Castro, D., additional, Cavazzuti, E., additional, Charles, E., additional, Chaty, S., additional, Chen, S., additional, Cheung, C. C., additional, Chiaro, G., additional, Ciprini, S., additional, Cohen-Tanugi, J., additional, Cominsky, L. R., additional, Coronado-Blázquez, J., additional, Costantin, D., additional, Cuoco, A., additional, Cutini, S., additional, D’Ammando, F., additional, DeKlotz, M., additional, Torre Luque, P. de la, additional, de Palma, F., additional, Desai, A., additional, Digel, S. W., additional, Lalla, N. Di, additional, Mauro, M. Di, additional, Venere, L. Di, additional, Domínguez, A., additional, Dumora, D., additional, Dirirsa, F. Fana, additional, Fegan, S. J., additional, Ferrara, E. C., additional, Franckowiak, A., additional, Fukazawa, Y., additional, Funk, S., additional, Fusco, P., additional, Gargano, F., additional, Gasparrini, D., additional, Giglietto, N., additional, Giommi, P., additional, Giordano, F., additional, Giroletti, M., additional, Glanzman, T., additional, Green, D., additional, Grenier, I. A., additional, Griffin, S., additional, Grondin, M.-H., additional, Grove, J. E., additional, Guiriec, S., additional, Harding, A. K., additional, Hayashi, K., additional, Hays, E., additional, Hewitt, J. W., additional, Horan, D., additional, Jóhannesson, G., additional, Johnson, T. J., additional, Kamae, T., additional, Kerr, M., additional, Kocevski, D., additional, Kovac’evic’, M., additional, Kuss, M., additional, Landriu, D., additional, Larsson, S., additional, Latronico, L., additional, Lemoine-Goumard, M., additional, Li, J., additional, Liodakis, I., additional, Longo, F., additional, Loparco, F., additional, Lott, B., additional, Lovellette, M. N., additional, Lubrano, P., additional, Madejski, G. M., additional, Maldera, S., additional, Malyshev, D., additional, Manfreda, A., additional, Marchesini, E. J., additional, Marcotulli, L., additional, Martí-Devesa, G., additional, Martin, P., additional, Massaro, F., additional, Mazziotta, M. N., additional, McEnery, J. E., additional, Mereu, I., additional, Meyer, M., additional, Michelson, P. F., additional, Mirabal, N., additional, Mizuno, T., additional, Monzani, M. E., additional, Morselli, A., additional, Moskalenko, I. V., additional, Negro, M., additional, Nuss, E., additional, Ojha, R., additional, Omodei, N., additional, Orienti, M., additional, Orlando, E., additional, Ormes, J. F., additional, Palatiello, M., additional, Paliya, V. S., additional, Paneque, D., additional, Pei, Z., additional, Peña-Herazo, H., additional, Perkins, J. S., additional, Persic, M., additional, Pesce-Rollins, M., additional, Petrosian, V., additional, Petrov, L., additional, Piron, F., additional, Poon, H., additional, Porter, T. A., additional, Principe, G., additional, Rainò, S., additional, Rando, R., additional, Razzano, M., additional, Razzaque, S., additional, Reimer, A., additional, Reimer, O., additional, Remy, Q., additional, Reposeur, T., additional, Romani, R. W., additional, Parkinson, P. M. Saz, additional, Schinzel, F. K., additional, Serini, D., additional, Sgrò, C., additional, Siskind, E. J., additional, Smith, D. A., additional, Spandre, G., additional, Spinelli, P., additional, Strong, A. W., additional, Suson, D. J., additional, Tajima, H., additional, Takahashi, M. N., additional, Tak, D., additional, Thayer, J. B., additional, Thompson, D. J., additional, Tibaldo, L., additional, Torres, D. F., additional, Torresi, E., additional, Valverde, J., additional, Klaveren, B. Van, additional, Zyl, P. van, additional, Wood, K., additional, Yassine, M., additional, and Zaharijas, G., additional

Published
2020
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50. VERITAS and Fermi-LAT Observations of TeV Gamma-Ray Sources Discovered by HAWC in the 2HWC Catalog

Author

Abeysekara, A. U., Archer, A., Benbow, W., Bird, R., Brose, R., Buchovecky, M., Buckley, J. H., Bugaev, V., Chromey, A. J., Connolly, M. P., Cui, W., Michael Daniel, Falcone, A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Hütten, M., Hanna, D., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Johnson, C. A., Kaaret, P., Kar, P., Kertzman, M., Kieda, D., Krause, M., Krennrich, F., Kumar, S., Lang, M. J., Lin, T. T. Y., Mcarthur, S., Moriarty, P., Mukherjee, R., O’brien, S., Ong, R. A., Otte, A. N., Park, N., Petrashyk, A., Pohl, M., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Richards, G. T., Roache, E., Rulten, C., Sadeh, I., Santander, M., Sembroski, G. H., Shahinyan, K., Sushch, I., Tyler, J., Wakely, S. P., Weinstein, A., Wells, R. M., Wilcox, P., Wilhelm, A., Williams, D. A., Williamson, T. J., Zitzer, B., Veritas, The Collaboration, Abdollahi, S., Ajello, M., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Berenji, B., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, E., Brandt, T. J., Bruel, P., Buehler, R., Cameron, R. A., Caputo, R., Caraveo, P. A., Castro, D., Cavazzuti, E., Charles, E., Chiaro, G., Ciprini, S., Cohen-Tanugi, J., Costantin, D., Cutini, S., D’ammando, F., Palma, F., Di Lalla, N., Di Mauro, M., Di Venere, L., Domínguez, A., Favuzzi, C., Fegan, S. J., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guillemot, L., Guiriec, S., Hays, E., Hewitt, J. W., Horan, D., Jóhannesson, G., Kensei, S., Kuss, M., Larsson, S., Latronico, L., Lemoine-Goumard, M., Li, J., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Magill, J. D., Maldera, S., Mazziotta, M. N., Mcenery, J. E., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Ojha, R., Omodei, N., Orienti, M., Orlando, E., Palatiello, M., Paliya, V. S., Paneque, D., Perkins, J. S., Persic, M., Pesce-Rollins, M., Petrosian, V., Piron, F., Porter, T. A., Principe, G., Rainò, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Reposeur, T., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Thayer, J. B., Thompson, D. J., Torres, D. F., Tosti, G., Troja, E., Valverde, J., Vianello, G., Vogel, M., Wood, K., Yassine, M., The Fermi-LAT Collaboration, Alfaro, R., Álvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Avila Rojas, D., Ayala Solares, H. A., Becerril, A., Belmont-Moreno, E., Benzvi, S. Y., Bernal, A., Braun, J., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., Coutiño León, S., León, C., La Fuente, E., Dichiara, S., Dingus, B. L., Duvernois, M. A., Díaz-Vélez, J. C., Engel, K., Enriquez-Rivera, O., Fiorino, D. W., Fleischhack, H., Fraija, N., García-González, J. A., Garfias, F., González Muñoz, A., González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hernandez-Almada, A., Hona, B., Hueyotl-Zahuantitla, F., Hui, C. M., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., León Vargas, H., Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Luna-García, R., López-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Salesa Greus, F., Sandoval, A., Schneider, M., Seglar Arroyo, M., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. 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U., Archer, A., Benbow, W., Bird, R., Brose, R., Buchovecky, M., Buckley, J. H., Bugaev, V., Chromey, A. J., Connolly, M. P., Cui, W., Daniel, M. K., Falcone, A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Hutten, M., Hanna, D., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Johnson, C. A., Kaaret, P., Kar, P., Kertzman, M., Kieda, D., Krause, M., Krennrich, F., Kumar, S., Lang, M. J., Lin, T. T. Y., Mcarthur, S., Moriarty, P., Mukherjee, R., O'Brien, S., Ong, R. A., Otte, A. N., Park, N., Petrashyk, A., Pohl, M., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Richards, G. T., Roache, E., Rulten, C., Sadeh, I., Santander, M., Sembroski, G. H., Shahinyan, K., Sushch, I., Tyler, J., Wakely, S. P., Weinstein, A., Wells, R. M., Wilcox, P., Wilhelm, A., Williams, D. A., Williamson, T. J., Zitzer, B., Abdollahi, S., Ajello, M., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Berenji, B., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, E., Brandt, T. J., Bruel, P., Buehler, R., Cameron, R. A., Caputo, R., Caraveo, P. A., Castro, D., Cavazzuti, E., Charles, E., Chiaro, G., Ciprini, S., Cohen-Tanugi, J., Costantin, D., Cutini, S., D'Ammando, F., DE PALMA, Francesco, Lalla, N. D., Mauro, M. D., Venere, L. D., Dominguez, A., Favuzzi, C., Fegan, S. J., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guillemot, L., Guiriec, S., Hays, E., Hewitt, J. W., Horan, D., Johannesson, G., Kensei, S., Kuss, M., Larsson, S., Latronico, L., Lemoine-Goumard, M., Li, J., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Magill, J. D., Maldera, S., Mazziotta, M. N., Mcenery, J. E., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Ojha, R., Omodei, N., Orienti, M., Orlando, E., Palatiello, M., Paliya, V. S., Paneque, D., Perkins, J. S., Persic, M., Pesce-Rollins, M., Petrosian, V., Piron, F., Porter, T. A., Principe, G., Raino, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Reposeur, T., Sgro, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Thayer, J. B., Thompson, D. J., Torres, D. F., Tosti, G., Troja, E., Valverde, J., Vianello, G., Vogel, M., Wood, K., Yassine, M., Alfaro, R., Alvarez, C., Alvarez, J. D., Arceo, R., Arteaga-Velazquez, J. C., Rojas, D. A., Solares, H. A. A., Becerril, A., Belmont-Moreno, E., Benzvi, S. Y., Bernal, A., Braun, J., Brisbois, C., Caballero-Mora, K. S., Capistran, T., Carraminana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., De Leon, S. C., Leon, C. D., Fuente, E. D. L., Dichiara, S., Dingus, B. L., Duvernois, M. A., Diaz-Velez, J. C., Engel, K., Enriquez-Rivera, O., Fiorino, D. W., Fleischhack, H., Fraija, N., Garcia-Gonzalez, J. A., Garfias, F., Munoz, A. G., Gonzalez, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hernandez-Almada, A., Hona, B., Hueyotl-Zahuantitla, F., Hui, C. M., Huntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. L., Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Luna-Garcia, R., Lopez-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martinez-Castro, J., Martinez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafa, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Perez-Perez, E. G., Ren, Z., Rho, C. D., Riviere, C., Rosa-Gonzalez, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Greus, F. S., Sandoval, A., Schneider, M., Arroyo, M. S., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Villasenor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Yodh, G., Zepeda, A., Zhou, H., ITA, 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), Hütten, M., Palma, F. De, Lalla, N. Di, Mauro, M. Di, Venere, L. Di, Jóhannesson, G., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Capistrán, T., De León, S. Coutino, León, C. De, Fuente, E. De La, Diaz-Vélez, J. C., Garcia-González, J. A., Munoz, A. González, González, M. M., Hüntemeyer, P., Vargas, H. León, López-Coto, R., Mostafá, M., Pérez-Pérez, E. G., Rosa-González, D., Greus, F. Salesa, and Arroyo, M. Seglar

Subjects
Physics, High energy, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Institut für Physik und Astronomie, Astronomy and Astrophysics, Astrophysics, gamma rays: general, Astronomy and Astrophysic, 01 natural sciences, Pulsar wind nebula, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], 0103 physical sciences, ddc:520, ddc:530, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, general [gamma rays], Cherenkov radiation, Fermi Gamma-ray Space Telescope
Abstract

International audience; The High Altitude Water Cherenkov (HAWC) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100 GeV) gamma-ray sources based on 507 days of observation. Among these, 19 sources are not associated with previously known teraelectronvolt (TeV) gamma-ray sources. We have studied 14 of these sources without known counterparts with VERITAS and Fermi-LAT. VERITAS detected weak gamma-ray emission in the 1 TeV–30 TeV band in the region of DA 495, a pulsar wind nebula coinciding with 2HWC J1953+294, confirming the discovery of the source by HAWC. We did not find any counterpart for the selected 14 new HAWC sources from our analysis of Fermi-LAT data for energies higher than 10 GeV. During the search, we detected gigaelectronvolt (GeV) gamma-ray emission coincident with a known TeV pulsar wind nebula, SNR G54.1+0.3 (VER J1930+188), and a 2HWC source, 2HWC J1930+188. The fluxes for isolated, steady sources in the 2HWC catalog are generally in good agreement with those measured by imaging atmospheric Cherenkov telescopes. However, the VERITAS fluxes for SNR G54.1+0.3, DA 495, and TeV J2032+4130 are lower than those measured by HAWC, and several new HAWC sources are not detected by VERITAS. This is likely due to a change in spectral shape, source extension, or the influence of diffuse emission in the source region.

Published
2018
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