Now showing items 1-20 of 469

    • 0FGL J1830.3+0617: A FERMI BLAZAR NEAR THE GALACTIC PLANE 

      Mirabal, N.; Halpern, J. P. (IOP, 2009-08-10)
      aas-2018.png iop-2016.png 0FGL J1830.3+0617: A FERMI BLAZAR NEAR THE GALACTIC PLANE N. Mirabal1,3 and J. P. Halpern2 Published 10 August 2009 • © 2009. The American Astronomical Society. All rights ...
    • 2 mm GISMO Observations of the Galactic Center. I. Dust Emission 

      Arendt, Richard G; Staguhn, Johannes; Dwek, Eli; Morris, Mark R; Yusef-Zadeh, Farhad; Benford, Dominic J; Kovacs, Attila; Gonzalez-Quiles, Junellie (The American Astronomical Society, 2019-11-01)
      The Central Molecular Zone (CMZ), covering the inner ∼ 1 ◦ of the Galactic plane has been mapped at 2 mm using the GISMO bolometric camera on the 30 m IRAM telescope. The 2100 resolution maps show abundant emission from ...
    • 2 mm GISMO Observations of the Galactic Center. II. A Nonthermal Filament in the Radio Arc and Compact Sources 

      Staguhn, Johannes; Arendt, Richard G; Dwek, Eli; Morris, Mark R; Yusef-Zadeh, Farhad; Benford, Dominic J; Kovacs, Attila; Gonzalez-Quiles, Junellie (The American Astronomical Society, 2019-11-01)
      We have used the Goddard IRAM 2-Millimeter Observer (GISMO) with the 30 m IRAM telescope to carry out a 2 mm survey of the Galaxy’s central molecular zone (CMZ). These observations detect thermal emission from cold ISM ...
    • The 2001 Superoutburst of WZ Sagittae 

      Patterson, Joseph; Masi, Gianluca; Richmond, Michael W.; Martin, Brian; Beshore, Edward; Skillman, David R.; Kemp, Jonathan; Vanmunster, Tonny; Rea, Robert; Allen, William; Davis, Stacey; Davis, Tracy; Henden, Arne A.; Starkey, Donn; Foote, Jerry; Oksanen, Arto; Cook, Lewis M.; Fried, Robert E.; Husar, Dieter; Novák, Rudolf; Campbell, Tut; Robertson, Jeff; Krajci, Thomas; Pavlenko, Elena; Mirabal, Nestor; Niarchos, Panos G.; Brettman, Orville; Walker, Stan (IOP, 2002-06-10)
      We report the results of a worldwide campaign to observe WZ Sagittae during its 2001 superoutburst. After a 23 yr slumber at V = 15.5, the star rose within 2 days to a peak brightness of 8.2, and showed a main eruption ...
    • 2FHL: THE SECOND CATALOG OF HARD FERMI-LAT SOURCES 

      Mirabal, N.; Buson, S.; et al. (IOP, 2016-01-14)
      We present a catalog of sources detected above 50 GeV by the Fermi-Large Area Telescope (LAT) in 80 months of data. The newly delivered Pass 8 event-level analysis allows the detection and characterization of sources in ...
    • 3FGL DEMOGRAPHICS OUTSIDE THE GALACTIC PLANE USING SUPERVISED MACHINE LEARNING: PULSAR AND DARK MATTER SUBHALO INTERPRETATIONS 

      Mirabal, N.; Charles, E.; Ferrara, E. C.; Gonthier, P. L.; Harding, A. K.; Sánchez-Conde, M. A.; Thompson, D.J. (IOP, 2016-06-29)
      Nearly one-third of the sources listed in the Third Fermi Large Area Telescope (LAT) catalog (3FGL) remain unassociated. It is possible that predicted and even unanticipated gamma-ray source classes are present in these ...
    • 3FHL: The Third Catalog of Hard Fermi-LAT Sources 

      Mirabal, N.; et al. (IOP, 2017-09-27)
      We present a catalog of sources detected above 10 GeV by the Fermi Large Area Telescope (LAT) in the first 7 years of data using the Pass 8 event-level analysis. This is the Third Catalog of Hard Fermi-LAT Sources (3FHL), ...
    • The Accretion History of AGN: A Newly Defined Population of Cold Quasars 

      Kirkpatrick, Allison; Urry, C. Megan; Brewster, Jason; Cooke, Kevin C.; Estrada, Michael; Glikman, Eilat; Hamblin, Kurt; Ananna, Tonima Tasnim; Carlile, Casey; Coleman, Brandon; Johnson, Jordan; Kartaltepe, Jeyhan S.; LaMassa, Stephanie M.; Marchesi, Stefano; Powell, Meredith; Sanders, Dave; Treister, Ezequiel; Turner, Tracey Jane (2019-08-15)
      Quasars are the most luminous of active galactic nuclei (AGN), and are perhaps responsible for quenching star formation in their hosts. The Stripe 82X catalog covers 31.3 deg² of the Stripe 82 field, of which the 15.6 deg² ...
    • Accurate Astrometry of 22 Southern Hemisphere Radio Sources 

      Fey, Alan L.; Ojha, Roopesh; Jauncey, David L.; Johnston, Kenneth J.; Reynolds, John E.; Lovell, James E. J.; Tzioumis, Anastasios K.; Quick, Jonathan F. H.; Nicolson, George D.; Ellingsen, Simon P.; McCulloch, Peter M.; Koyama, Yasuhiro (IOP, 2003-12-03)
      Milliarcsecond-accurate radio positions for 22 southern hemisphere extragalactic sources are reported. These positions are derived from Mark III very long baseline interferometry observations made between 2003 February and ...
    • Active Galactic Nuclei under the scrutiny of CTA 

      Sol, H.; Zech, A.; Boisson, C.; Almeida, U. Barres de; Biteau, J.; Contreras, J.-L.; Giebels, B.; Hassan, T.; Inoue, Y.; Katarzynsk, K.; Krawczynski, H.; Mirabal, N.; Poutanen, J.; Rieger, F.; Totani, T.; Benbow, W.; Cerruti, M.; Errando, M.; Fallon, L.; Pino, E. de Gouveia Dal; Hinton, J.A.; Inoue, S.; Lenain, J.-P.; Neronov, A.; Takahashi, K.; Takami, H.; White, R. (Elsevier, 2012-12-20)
      Active Galactic Nuclei (hereafter AGN) produce powerful outflows which offer excellent conditions for efficient particle acceleration in internal and external shocks, turbulence, and magnetic reconnection events. The jets ...
    • Advanced fabrication technologies for ultraprecise replicated mirrors for x-ray telescopes 

      Mimura, Hidekazu; Yamaguchi, Gota; Kume, Takehiro; Takeo, Yoko; Ito, Akinari; Matsuzawa, Yusuke; Saito, Takahiro; Hiraguri, Kentarou; Takehara, Yusuke; Takigawa, Ayumu; Tamura, Keisuke; Kanoh, Tetsuo; Tachibana, Kenji; Hashizume, Hirokazu; Mitsuishi, Ikuyuki (SPIE, 2020-12-13)
      For many years, Wolter mirrors have been used as imaging elements in X-ray telescopes. The shape error of Wolter mirrors fabricated by replicating the shape of a mandrel originates from the replication error in electroforming. ...
    • THE AFTERGLOWS OF SWIFT-ERA GAMMA-RAY BURSTS. I. COMPARING PRE-SWIFT AND SWIFT-ERA LONG/SOFT (TYPE II) GRB OPTICAL AFTERGLOWS 

      Mirabal, N. (IOP, 2010-08-23)
      We have gathered optical photometry data from the literature on a large sample of Swift-era gamma-ray burst (GRB) afterglows including GRBs up to 2009 September, for a total of 76 GRBs, and present an additional three ...
    • AGN Forecasting 

      Hassan, Tarek; Mirabal, Nestor; Contreras, Jose Luis; the CTA Consortium (POS, 2012-06-20)
      The First Fermi-LAT catalog (1FGL) represents the most complete list of sources in the GeV sky to date. We use the reported 1FGL spectral parameters to extrapolate Fermi AGN spectra to the very-high energy (VHE) range (15 ...
    • AGN TXS 1923+123 

      Carpenter, Bryce; Ojha, Roopesh (The Astronomer's Telegram, 2016-01-01)
    • THE ALGOL TRIPLE SYSTEM SPATIALLY RESOLVED AT OPTICAL WAVELENGTHS 

      Zavala, R. T.; Hummel, C. A.; Boboltz, D. A.; Ojha, R.; Shaffer, D. B.; Tycner, C.; Richards, M. T.; Hutter, D. J. (IOP, 2010-04-30)
      Interacting binaries typically have separations in the milliarcsecond regime, and hence it has been challenging to resolve them at any wavelength. However, recent advances in optical interferometry have improved our ability ...
    • All-sky Medium Energy Gamma-ray Observatory: Exploring the Extreme Multimessenger Universe 

      McEnery, Julie E.; Ojha, R.; Georganopoulos, Markos; Meyer, Eileen (2019-07-10)
      The All-sky Medium Energy Gamma-ray Observatory (AMEGO) is a probe class mission concept that will provide essential contributions to multimessenger astrophysics in the late 2020s and beyond. AMEGO combines high sensitivity ...
    • An Analysis of the North Polar Spur Using HaloSat 

      LaRocca, Daniel M.; Kaaret, Philip; Kuntz, K. D.; Hodges-Kluck, Edmund; Zajczyk, Anna; Bluem, Jesse; Ringuette, Rebecca; Jahoda, Keith M. (IOP, 2020-11-20)
      We present HaloSat X-ray observations of the entirety of the bright X-ray emitting feature known as the North Polar Spur (NPS). The large field of view of HaloSat enabled coverage of the entire bright NPS in only 14 fields, ...
    • Angular Broadening of Intraday Variable AGNs. II. Interstellar and Intergalactic Scattering 

      Lazio, T. Joseph W.; Ojha, Roopesh; Fey, Alan L.; Kedziora-Chudczer, Lucyna; Cordes, James M.; Jauncey, David L.; Lovell, James E. J. (IOP, 2008-01-01)
      We analyze a sample of 58 multiwavelength, Very Long Baseline Array observations of active galactic nuclei (AGNs) to determine their scattering properties. Approximately 75% of the sample consists of AGNs that ...
    • Annihilating dark matter or noise?: A statistical examination of the Fermi GeV excess around the Galactic Centre 

      Mirabal, N. (2019-04-05)
      Excess Fermi GeV emission around the Galactic Centre has been interpreted as a possible signature of annihilating dark matter. Here we analyse three aspects of this claim: its spectral cutoff, the correlation between the ...
    • The Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) 

      Stark, Antony A.; Bally, John; Balm, Simon P.; Bania, T. M.; Bolatto, Alberto D.; Chamberlin, Richard A.; Engargiola, Gregory; Huang, Maohai; Ingalls, James G.; Jacobs, Karl; Jackson, James M.; Kooi, Jacob W.; Lane, Adair P.; Lo, K.-Y.; Marks, Rodney D.; Martin, Christopher L.; Mumma, Dennis; Ojha, Roopesh; Schieder, Rudolf; Staguhn, Johannes; Stutzki, Juergen; Walker, Christopher K.; Wilson, Robert W.; Wright, Gregory A.; Zhang, Xiaolei; Zimmermann, Peter; Zimmermann, Ruediger (IOP, 2000-12-15)
      AST/RO, a 1.7 m diameter telescope for astronomy and aeronomy studies at wavelengths between 200 and 2000 microns, was installed at the South Pole during the 1994-1995 Austral summer. The telescope operates continuously ...