Browsing by Author "Loeb, Abraham"

Now showing items 21-40 of 70

    • Electromagnetic Counterparts to Black Hole Mergers Detected by LIGO 

      Loeb, Abraham (American Astronomical Society, 2016)
      Mergers of stellar-mass black holes (BHs), such as GW150914 observed by LIGO, are not expected to have electromagnetic counterparts. However, the Fermi GBM detector identified of a gamma-ray transient 0.4 s after the ...

    • The event horizon of Sagittarius A* 

      Broderick, Avery E.; Loeb, Abraham; Narayan, Ramesh (IOP Publishing, 2009)
      Black hole event horizons, causally separating the external universe from compact regions of spacetime, are one of the most exotic predictions of general relativity. Until recently, their compact size has prevented efforts ...

    • Evidence for a direct collapse black hole in the Lyman α source CR7 

      Smith, Aaron; Bromm, Volker; Loeb, Abraham (Oxford University Press (OUP), 2016)
      Throughout the epoch of reionization the most luminous Ly{\alpha} emitters are capable of ionizing their own local bubbles. The CR7 galaxy at z≈6.6 stands out for its combination of exceptionally bright Ly{\alpha} and HeII ...

    • Fast Radio Bursts from Extragalactic Light Sails 

      Lingam, Manasvi; Loeb, Abraham (American Astronomical Society, 2017)
      We examine the possibility that Fast Radio Bursts (FRBs) originate from the activity of extragalactic civilizations. Our analysis shows that beams used for powering large light sails could yield parameters that are consistent ...

    • First limits on the 21 cm power spectrum during the Epoch of X-ray heating 

      Ewall-Wice, A.; Dillon, Joshua S.; Hewitt, J. N.; Loeb, Abraham; Mesinger, A.; Neben, A. R.; Offringa, A. R.; Tegmark, M.; Barry, N.; Beardsley, A. P.; Bernardi, G.; Bowman, Judd D.; Briggs, F.; Cappallo, R. J.; Carroll, P.; Corey, B. E.; de Oliveira-Costa, A.; Emrich, D.; Feng, L.; Gaensler, B; Goeke, R.; Greenhill, Lincoln Jared; Hazelton, B. J.; Hurley-Walker, N.; Johnston-Hollitt, M.; Jacobs, Daniel C.; Kaplan, D. L.; Kasper, Justin C.; Kim, HS; Kratzenberg, E.; Lenc, E.; Line, J.; Lonsdale, C. J.; Lynch, M. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Thyagarajan, Nithyanandan; Oberoi, D.; Ord, S; Paul, S.; Pindor, B.; Pober, J. C.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A. E. E.; Roshi, A.; Shankar, N. Udaya; Sethi, Shiv K.; Srivani, K. S.; Subrahmanyan, R.; Sullivan, I. S.; Tingay, S. J.; Trott, C. M.; Waterson, M.; Wayth, R. B.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L.; Wu, C.; Wyithe, J. S. B. (Oxford University Press (OUP), 2016)
      We present first results from radio observations with the Murchison Widefield Array seeking to constrain the power spectrum of 21 cm brightness temperature fluctuations between the redshifts of 11.6 and 17.9 (113 and 75 ...

    • First Season MWA EoR Power Spectrum Results at Redshift 7 

      Beardsley, A.; Hazelton, B.; Sullivan, I.; Carroll, P.; Barry, N.; Rahimi, M.; Pindor, B.; Trott, C.; Line, J.; Jacobs, Daniel; Morales, M.; Pober, J.; Bernardi, G.; Bowman, Judd; Busch, M.; Briggs, F.; Cappallo, R.; Corey, B.; de Oliveira-Costa, A.; Dillon, Joshua; Emrich, D.; Ewall-Wice, A.; Feng, L.; Gaensler, B.; Goeke, R.; Greenhill, L.; Hewitt, J.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kaplan, D.; Kasper, Justin C.; Kim, Hanna; Kratzenberg, E.; Lenc, E.; Loeb, Abraham; Lonsdale, C.; Lynch, M.; McKinley, B.; McWhirter, S.; Mitchell, D.; Morgan, E.; Neben, A.; Thyagarajan, Nithyanandan; Oberoi, D.; Offringa, A.; Ord, S.; Paul, S.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A.; Roshi, A.; Shankar, N.; Sethi, Shiv; Srivani, K.; Subrahmanyan, R.; Tegmark, M.; Tingay, S.; al, et (American Astronomical Society, 2016)
      The Murchison Widefield Array (MWA) has collected hundreds of hours of Epoch of Reionization (EoR) data and now faces the challenge of overcoming foreground and systematic contamination to reduce the data to a cosmological ...

    • Future Probes of Cosmology and the High-Redshift Universe 

      Visbal, Elijah Francis (2013-10-08)
      This thesis is a study in theoretical cosmology with an emphasis on the high-redshift universe and promising directions for future observations. In Chapters 2 and 3, we propose intensity mapping of spectral line emission ...

    • A high reliability survey of discrete Epoch of Reionization foreground sources in the MWA EoR0 field 

      Carroll, P. A.; Line, J.; Morales, M. F.; Barry, N.; Beardsley, A. P.; Hazelton, B. J.; Jacobs, D. C.; Pober, J. C.; Sullivan, I. S.; Webster, R. L.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Corey, B. E.; de Oliveira-Costa, A.; Dillon, J. S.; Emrich, D.; Ewall-Wice, A.; Feng, L.; Gaensler, B; Goeke, R.; Greenhill, Lincoln Jared; Hewitt, J. N.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kaplan, D. L.; Kasper, Justin C.; Kim, HS.; Kratzenberg, E.; Lenc, E.; Loeb, Abraham; Lonsdale, C. J.; Lynch, M. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morgan, E.; Neben, A. R.; Oberoi, D.; Offringa, A. R.; Ord, S; Paul, S.; Pindor, B.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A. E. E.; Roshi, A.; Shankar, N. Udaya; Sethi, S. K.; Srivani, K. S.; Subrahmanyan, R.; Tegmark, M.; Thyagarajan, Nithyanandan; Tingay, S. J.; Trott, C. M.; Waterson, M.; Wayth, R. B.; Whitney, A. R.; Williams, A.; Williams, C. L.; Wu, C.; Wyithe, J. S. B. (Oxford University Press (OUP), 2016)
      Detection of the Epoch of Reionization HI signal requires a precise understanding of the intervening galaxies and AGN, both for instrumental calibration and foreground removal. We present a catalogue of 7394 extragalactic ...

    • The Importance of Wide-Field Foreground Removal for 21 Cm Cosmology: A Demonstration With Early MWA Epoch of Reionization Observations 

      Pober, J. C.; Hazelton, B. J.; Beardsley, A. P.; Barry, N. A.; Martinot, Z. E.; Sullivan, I. S.; Morales, M. F.; Bell, M. E.; Bhat, N. D. R.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Carroll, P.; Corey, B. E.; de Oliveira-Costa, A.; Deshpande, A. A.; Dillon, Joshua. S.; Emrich, D.; Ewall-Wice, A. M.; Feng, L.; Goeke, R.; Hewitt, J. N.; Hindson, L.; Hurley-Walker, N.; Jacobs, D. C.; Johnston-Hollitt, M.; Kaplan, D. L.; Kim, Han-Seek; Kittiwisit, P.; Kratzenberg, E.; Kudryavtseva, N.; Lenc, E.; Line, J.; Loeb, Abraham; Lonsdale, C. J.; Lynch, M. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morgan, E.; Neben, A. R.; Oberoi, D.; Offringa, A. R.; Ord, S; Paul, Sourabh; Pindor, B.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A. E. E.; Roshi, A.; Sethi, Shiv K.; Shankar, N. Udaya; Srivani, K. S.; Subrahmanyan, R.; Tegmark, M.; Thyagarajan, Nithyanandan; Tingay, S. J.; Trott, C. M.; Waterson, M.; Wayth, R. B.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L.; Wyithe, J. S. B.; Bernardi, Gianni; Greenhill, Lincoln; Kasper, Justin (American Astronomical Society, 2016)
      In this paper we present observations, simulations, and analysis demonstrating the direct connection between the location of foreground emission on the sky and its location in cosmological power spectra from interferometric ...

    • Inferring the Composition of Super-Jupiter Mass Companions of Pulsars with Radio Line Spectroscopy 

      Ray, Alak; Loeb, Abraham (American Astronomical Society, 2017)
      We propose using radio line spectroscopy to detect molecular absorption lines (such as OH at 1.6-1.7 GHz) before and after the total eclipse of black widow (BW) and other short orbital period binary pulsars with low mass ...

    • The Interaction of Relativistic Spacecrafts with the Interstellar Medium 

      Hoang, Thiem; Lazarian, A.; Burkhart, Blakesley K.; Loeb, Abraham (American Astronomical Society, 2017)
      The Breakthrough Starshot initiative aims to launch a gram-scale spacecraft to a speed of v∼0.2c, capable of reaching the nearest star system, α Centauri, in about 20 years. However, a critical challenge for the initiative ...

    • Interferometric Measurement of Acceleration at Relativistic Speeds 

      Christian, Pierre; Loeb, Abraham (American Astronomical Society, 2017)
      We show that an interferometer moving at a relativistic speed relative to a point source of light offers a sensitive probe of acceleration. Such an accelerometer contains no moving parts, and is thus more robust than ...

    • Jet-Launching Structure Resolved Near the Supermassive Black Hole in M87 

      Doeleman, Sheperd Samuel; Fish, V. L.; Schenck, D. E.; Beaudoin, C.; Blundell, Raymond; Bower, G. C.; Broderick, Alithia Carol; Chamberlin, R.; Freund, R.; Friberg, P.; Gurwell, Mark Andrew; Ho, Po-Yi; Honma, M.; Inoue, M.; Krichbaum, T. P.; Lamb, J; Loeb, Abraham; Lonsdale, C.; Marrone, D. P.; Moran, James M.; Oyama, T.; Plambeck, R.; Primiani, Rurik A.; Rogers, A. E. E.; Smythe, D. L.; SooHoo, J.; Strittmatter, P.; Tilanus, R. P. J.; Titus, M.; Weintroub, Jonathan; Wright, Bennett Bennett; Young, K. H.; Ziurys, L. M. (American Association for the Advancement of Science (AAAS), 2012)
      Approximately 10% of active galactic nuclei exhibit relativistic jets, which are powered by accretion of matter onto super massive black holes. While the measured width profiles of such jets on large scales agree with ...

    • Jetted tidal disruptions of stars as a flag of intermediate mass black holes at high redshifts 

      Fialkov, Anastasia; Loeb, Abraham (Oxford University Press (OUP), 2017-07-14)
      Tidal disruption events (TDEs) of stars by single or binary supermassive black holes (SMBHs) brighten galactic nuclei and reveal a population of otherwise dormant black holes. Adopting event rates from the literature, we ...

    • Large-Scale Distribution of Total Mass versus Luminous Matter from Baryon Acoustic Oscillations: First Search in the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey Data Release 10 

      Soumagnac, M. T.; Barkana, R.; Sabiu, C. G.; Loeb, Abraham; Ross, A. J.; Abdalla, F. B.; Balan, S. T.; Lahav, O. (American Physical Society (APS), 2016)
      Baryon Acoustic Oscillations (BAOs) in the early Universe are predicted to leave an as yet undetected signature on the relative clustering of total mass versus luminous matter. A detection of this effect would provide an ...

    • Lessons from Mayan Astronomy 

      Loeb, Abraham
      The Mayan culture collected exquisite astronomical data for over a millennium. However, it failed to come up with the breakthrough ideas of modern astronomy because the data was analyzed within a mythological culture of ...

    • Limits on Intergalactic Dust During Reionization 

      Imara, Nia; Loeb, Abraham (American Astronomical Society, 2016)
      In this Letter, we constrain the dust-to-gas ratio in the intergalactic medium (IGM) at high redshifts. We employ models for dust in the local Universe to contrain the dust-to-gas ratio during the epoch of reionization at ...

    • LISA detection of binary black holes in the Milky Way galaxy 

      Christian, Pierre; Loeb, Abraham (Oxford University Press (OUP), 2017-04-17)
      Using the black hole merger rate inferred from LIGO, we calculate the abundance of tightly bound black hole binaries in the Milky Way galaxy. Binaries with a small semimajor axis (≲10R⊙) originate at larger separations ...

    • Low frequency observations of linearly polarized structures in the interstellar medium near the south Galactic pole 

      Lenc, E.; Gaensler, B; Sun, X. H.; Sadler, E. M.; Willis, A. G.; Barry, N.; Beardsley, A. P.; Bell, M. E.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Callingham, J. R.; Cappallo, R. J.; Carroll, P.; Corey, B. E.; Oliveira-Costa, A. de; Deshpande, A. A.; Dillon, J. S.; Dwarkanath, K. S.; Emrich, D.; Ewall-Wice, A.; Feng, L.; For, B.-Q.; Goeke, R.; Greenhill, Lincoln Jared; Hancock, P.; Hazelton, B. J.; Hewitt, J. N.; Hindson, L.; Hurley-Walker, N.; Johnston-Hollitt, M.; Jacobs, D. C.; Kapińska, A. D.; Kaplan, D. L.; Kasper, Justin C.; Kim, H.-S.; Kratzenberg, E.; Line, J.; Loeb, Abraham; Lonsdale, C. J.; Lynch, M. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Murphy, T.; Neben, A. R.; Oberoi, D.; Offringa, A. R.; Ord, S; Paul, S.; Pindor, B.; Pober, J. C.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A. E. E.; Roshi, A. (American Astronomical Society, 2016)
      We present deep polarimetric observations at 154 MHz with the Murchison Widefield Array (MWA), covering 625 deg^2 centered on RA=0 h, Dec=-27 deg. The sensitivity available in our deep observations allows an in-band, ...

    • Lyman α Radiation Hydrodynamics of Galactic Winds Before Cosmic Reionization 

      Smith, Aaron; Bromm, Volker; Loeb, Abraham (Oxford University Press (OUP), 2016)
      The dynamical impact of Lyman-alpha (Ly{\alpha}) radiation pressure on galaxy formation depends on the rate and duration of momentum transfer between Ly{\alpha} photons and neutral hydrogen gas. Although photon trapping ...