Search Publications
Discovery of Variability of the Progenitor of SN 2011dh in M 51 Using the Large Binocular Telescope
Kochanek, C. S.; Stanek, K. Z.; Gerke, J. R. +1 more
We show that the candidate progenitor of the core-collapse SN 2011dh in M 51 (8 Mpc away) was fading by 0.039 ± 0.006 mag yr-1 during the 3 years prior to the supernova, and that this level of variability is moderately unusual for other similar stars in M 51. While there are uncertainties about whether the true progenitor was a blue com…
Metallicities of Emission-line Galaxies from HST ACS PEARS and HST WFC3 ERS Grism Spectroscopy at 0.6 < z < 2.4
Pirzkal, Nor; Cohen, Seth; Windhorst, Rogier A. +9 more
Galaxies selected on the basis of their emission-line strength show low metallicities, regardless of their redshifts. We conclude this from a sample of faint galaxies at redshifts between 0.6 < z < 2.4, selected by their prominent emission lines in low-resolution grism spectra in the optical with the Advanced Camera for Surveys on the Hubble…
A superburst candidate in EXO 1745-248 as a challenge to thermonuclear ignition models
Altamirano, D.; Degenaar, N.; Wijnands, R. +6 more
We report on Chandra, Rossi X-ray Timing Explorer (RXTE), Swift/Burst Alert Telescope (BAT) and MAXI observations of an X-ray flare of ∼1 d and subsequent outburst of a transient X-ray source observed in 2011 October-November in the globular cluster Terzan 5. We show that the source is the same as the transient that was active in 2000, i.e. the ne…
The peculiar 2011 outburst of the black hole candidate IGR J17091-3624, a GRS 1915+105-like source?
Capitanio, F.; Ferrigno, C.; Bozzo, E. +3 more
We report on the long-term monitoring campaign of the black hole candidate IGR J17091-3624 performed with INTEGRAL and Swift during the peculiar outburst started on 2011 January. We have studied the two-month spectral evolution of the source in detail. Unlike the previous outbursts, the initial transition from the hard to the soft state in 2011 wa…
Mergers and interactions in Sloan Digital Sky Survey type 2 quasars at z∼ 0.3-0.4. SDSS J143027.66-005614.8: a case study
Villar-Martín, M.; Rose, M.; Cabrera Lavers, A. +3 more
We present a compilation of Hubble Space Telescope (HST) images of 58 luminous Sloan Digital Sky Survey (SDSS) type 2 active galactic nuclei (AGNs) at ?. Of these, 42 are type 2 quasars, which is a good representation of all optically selected SDSS type 2 quasars in this z range. We find that the majority of the host galaxies are ellipticals (30/4…
An HST search for planets in the lower main sequence of the globular cluster NGC 6397
Bedin, L. R.; Rich, R. M.; Piotto, G. +2 more
Searches for planetary transits carried out in open and globular clusters have to date yielded only a handful of weak, unconfirmed candidates. These results have been interpreted as either being insignificant, or evidence that the cluster chemical or dynamical environment inhibits planetary formation or survival. Most campaigns have been limited b…
Large-scale Magnetic Helicity Fluxes Estimated from MDI Magnetic Synoptic Charts over the Solar Cycle 23
Zhang, Hongqi; Yang, Shangbin
To investigate the characteristics of large-scale and long-term evolution of magnetic helicity with solar cycles, we use the method of Local Correlation Tracking to estimate the magnetic helicity evolution over solar cycle 23 from 1996 to 2009 using 795 MDI magnetic synoptic charts. The main results are as follows: the hemispheric helicity rule st…
Masses and accretion rates of supermassive black holes in active galactic nuclei from the INTEGRAL survey
Sazonov, S. Yu.; Khorunzhev, G. A.; Burenin, R. A. +1 more
The masses of 68 supermassive black holes (SMBHs) in nearby ( z < 0.15) active galactic nuclei (AGNs) detected by the INTEGRAL observatory in the hard X-ray energy band (17-60 keV) outside the Galactic plane (| b| 5°) have been estimated. Well-known relations between the SMBHmass and (1) the infrared luminosity of the stellar bulge (from 2MASS …
Hard X-Ray and Ultraviolet Observations of the 2005 January 15 Two-ribbon Flare
Qiu, J.; Cheng, J. X.; Kerr, G.
It is well known that two-ribbon flares observed in Hα and ultraviolet (UV) wavelengths mostly exhibit compact and localized hard X-ray (HXR) sources. In this paper, we present comprehensive analysis of a two-ribbon flare observed in UV 1600 Å by Transition Region and Coronal Explorer and in HXRs by Reuven Ramaty High Energy Solar Spectroscopic Im…
Dune fields on Mars: Recorders of a climate change?
Quantin, Cathy; Silvestro, Simone; Gardin, Emilie +2 more
Dunes have similar morphologies on the Earth and Mars. The main differences between Martian and terrestrial dunes are their size, which is larger on Mars, and their duration of formation, which is longer on Mars. As the characteristic time of Martian dunes is in the same order as that of the Martian climatic oscillations, Martian dunes could be re…