Search Publications
Mid-infrared Period-luminosity Relations of RR Lyrae Stars Derived from the WISE Preliminary Data Release
Bloom, Joshua S.; Richards, Joseph W.; Butler, Nathaniel R. +1 more
Interstellar dust presents a significant challenge to extending parallax-determined distances of optically observed pulsational variables to larger volumes. Distance ladder work at mid-infrared wavebands, where dust effects are negligible and metallicity correlations are minimized, has been largely focused on few-epoch Cepheid studies. Here we pre…
Testing Photometric Diagnostics for the Dynamical State and Possible Intermediate-mass Black Hole Presence in Globular Clusters
Baumgardt, Holger; Noyola, Eva
Surface photometry is a necessary tool to establish the dynamical state of star clusters. We produce realistic HST-like images from N-body models of star clusters with and without central intermediate-mass black holes (IMBHs) in order to measure their surface brightness profiles. The models contain ~600,000 individual stars, black holes of various…
Reverberation Mapping of the Intermediate-mass Nuclear Black Hole in SDSS J114008.71+030711.4
Kaspi, Shai; Kollatschny, Wolfram; Behar, Ehud +2 more
We present the results of a reverberation mapping (RM) campaign on the black hole (BH) associated with the active galactic nucleus (AGN) in SDSS J114008.71+030711.4 (hereafter GH08). This object is selected from a sample of 19 candidate intermediate-mass BHs (M BH < 106 M sun) found by Greene & Ho in the Slo…
The TeV Binary HESS J0632+057 in the Low and High X-Ray State
Rea, Nanda; Torres, Diego F.
We report on a 40 ks Chandra observation of the TeV emitting high-mass X-ray binary HESS J0632+057 performed in 2011 February during a high state of X-ray and TeV activity. We have used the ACIS-S camera in continuous clocking mode to search for a possible X-ray pulsar in this system. Furthermore, we compare the emission of the source during this …
The Faintest Radio Source Yet: Expanded Very Large Array Observations of the Gravitational Lens SDSS J1004+4112
Jackson, N.
We present new radio observations of the large-separation gravitationally lensed quasar SDSS J1004+4112, taken in a total of 6 hr of observations with the Expanded Very Large Array. The maps reach a thermal noise level of approximately 4 µJy. We detect four of the five lensed images at the 15-35 µJy level, representing a source of intr…
Intrinsic Shape of Star-forming BzK Galaxies at z ~ 2 in GOODS-N
Kajisawa, Masaru; Ohta, Kouji; Yabe, Kiyoto +2 more
We study the structure of star-forming galaxies at z ~ 2 in a Great Observatories Origins Deep Survey North field selected as star-forming BzK (sBzK) galaxies down to K AB < 24.0 mag. Among 1029 sBzK galaxies, 551 galaxies (54%) show a single component in the Advanced Camera for Survey (ACS)/F850LP image obtained with the Hubble Spac…
XMM-Newton Observations Reveal Very High X-ray Luminosity from the Carbon-rich Wolf-Rayet Star WR 48a
Skinner, Stephen L.; Zhekov, Svetozar A.; Gagné, Marc
We present XMM-Newton observations of the dusty Wolf-Rayet (W-R) star WR 48a. This is the first detection of this object in X-rays. The XMM-Newton EPIC spectra are heavily absorbed and the presence of numerous strong emission lines indicates a thermal origin of the WR 48a X-ray emission, with dominant temperature components at kT cool ≈…
Short-term Evolution of Coronal Hole Boundaries
Gallagher, Peter T.; Krista, Larisza D.; Bloomfield, D. Shaun
The interaction of open and closed field lines at coronal hole (CH) boundaries is widely accepted to be due to interchange magnetic reconnection. To date, it is unclear how the boundaries vary on short timescales and at what velocity this occurs. Here, we describe an automated boundary tracking method used to determine CH boundary displacements on…
Differential Rotation of the Ultraviolet Corona at Solar Maximum
Giordano, Silvio; Mancuso, Salvatore
Synoptic observations of the O VI 1032 Å spectral line from the UltraViolet Coronagraph Spectrometer (UVCS) telescope on board the Solar and Heliospheric Observatory (SOHO) have been analyzed in order to establish the rotational characteristics of the solar corona in the time interval from 1999 March 18 to 2002 December 31, corresponding to the ma…
Solar Wind and Coronal Bright Points inside Coronal Holes
Karachik, Nina V.; Pevtsov, Alexei A.
Observations of 108 coronal holes (CHs) from 1998-2008 were used to investigate the correlation between fast solar wind (SW) and several parameters of CHs. Our main goal was to establish the association between coronal bright points (CBPs; as sites of magnetic reconnection) and fast SW. Using in situ measurements of the SW, we have connected strea…