Search Publications
A Correlation between Galaxy Light Concentration and Supermassive Black Hole Mass
Graham, Alister W.; Trujillo, I.; Erwin, Peter +1 more
We present evidence for a strong correlation between the concentration of bulges and the mass of their central supermassive black hole (Mbh)-more concentrated bulges have more massive black holes. Using Cre(1/3) from Trujillo, Graham, & Caon as a measure of bulge concentration, we find that log(Mbh/M…
Radio Signatures of Coronal Mass Ejection Interaction: Coronal Mass Ejection Cannibalism?
Kaiser, M. L.; Howard, R. A.; Gopalswamy, N. +2 more
We report the first detection at long radio wavelengths of interaction between coronal mass ejections (CMEs) in the interplanetary medium. The radio signature is in the form of intense continuum-like radio emission following an interplanetary type II burst. At the time of the radio enhancement, coronagraphic images show a fast CME overtaking a slo…
Clear Evidence of Reconnection Inflow of a Solar Flare
Yokoyama, T.; Akita, K.; Morimoto, T. +2 more
We found an important piece of evidence for magnetic reconnection inflow in a flare on 1999 March 18. The flare occurred on the northeast limb, displaying a nice cusp-shaped soft X-ray loop and a plasmoid ejection typical for the long-duration events. The EUV observation of the same flare shows us a bubble-like void ejection. The core of this EUV …
A Possible Cepheid-like Luminosity Estimator for the Long Gamma-Ray Bursts
Ramirez-Ruiz, Enrico; Hurley, Kevin; Reichart, Daniel E. +3 more
We present a possible Cepheid-like luminosity estimator for the long gamma-ray bursts based on the variability of their light curves. To construct the luminosity estimator, we use CGRO/BATSE data for 13 bursts, Wind/Konus data for five bursts, Ulysses/GRB data for one burst, and NEAR/XGRS data for one burst. Spectroscopic redshifts, peak fluxes, a…
Observational Determination of the Rate of Magnetic Helicity Transport through the Solar Surface via the Horizontal Motion of Field Line Footpoints
Chae, Jongchul
Magnetic helicity may be transported to the solar corona through the solar surface either via the passage of helical magnetic field lines from below or via the shuffling of footpoints of preexisting coronal field lines. In this Letter, we show how to observationally determine the rate of magnetic helicity transport via photospheric footpoint shuff…
Chandra Observations of ``The Antennae'' Galaxies (NGC 4038/9)
Zezas, A.; Fabbiano, G.; Murray, S. S.
We report the results of a deep Chandra ACIS pointing at the merging system NGC 4038/9. We detect an extraordinarily luminous population of X-ray sources, with luminosity well above that of XRBs in M31 and the Milky Way. If these sources are unbeamed XRBs, our observations may point to them being 10-(a few)100 Msolar black hole counterp…
Investigation of Mass Flows beneath a Sunspot by Time-Distance Helioseismology
Zhao, Junwei; Kosovichev, Alexander G.; Duvall, Thomas L., Jr.
A time-distance helioseismic technique is employed to analyze a set of high-resolution Dopplergram observations of a large sunspot by SOHO/MDI on 1998 June 18. A regularized, damped least-squares inversion is applied to the measurements of travel times to infer mass flows around the sunspot below the solar surface. Powerful converging and downward…
Nuclear Luminosities and Radio Loudness of Seyfert Nuclei
Ho, Luis C.; Peng, Chien Y.
Historically, Seyfert nuclei have been considered to be radio-quiet active galactic nuclei (AGNs). We question this widely held assumption by showing that the distribution of the radio-to-optical luminosity ratio, R≡Lν(6 cm)/Lν(B), when properly measured for the nuclear component, places the majority of type 1 Seyfert nuclei …
Isocam-Cvf 5-12 Micron Spectroscopy of Ultraluminous Infrared Galaxies
Lutz, D.; Genzel, R.; Sturm, E. +10 more
We present low-resolution mid-infrared (MIR) spectra of 16 ultraluminous infrared galaxies (ULIRGs) obtained with the circular variable filter (CVF) spectroscopy mode of ISOCAM on board the Infrared Space Observatory (ISO). Our sample completes previous ISO spectroscopy of ultra- and hyperluminous infrared galaxies toward higher luminosities. The …
A New Measurement of the Primordial Abundance of Deuterium: Toward Convergence with the Baryon Density from the Cosmic Microwave Background?
Bowen, David V.; Pettini, Max
From the analysis of the near-UV spectrum of the quasar (QSO)2206-199, obtained with a long series of exposures with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, we deduce a value D/H=(1.65+/-0.35)×10-5 (1 σ error) for the abundance of deuterium in the zabs=2.0762 damped Lyα system (DLA) along this …