Search Publications
Searches for Millisecond Pulsar Candidates among the Unidentified Fermi Objects
Cheng, K. S.; Takata, J.; Kong, A. K. H. +9 more
Here we report the results of searching millisecond pulsar (MSP) candidates from the Fermi LAT second source catalog (2FGL). Seven unassociated γ-ray sources in this catalog are identified as promising MSP candidates based on their γ-ray properties. Through the X-ray analysis, we have detected possible X-ray counterparts, localized to an arcsecond…
The Role of Large Amplitude Upstream Low-frequency Waves in the Generation of Superthermal Ions at a Quasi-parallel Collisionless Shock: Cluster Observations
Wang, Shui; Huang, Can; Guo, Fan +3 more
The superthermal ions at a quasi-parallel collisionless shock are considered to be generated during the reformation of the shock. Recently, hybrid simulations of a quasi-parallel shock have shown that during the reformation of a quasi-parallel shock the large-amplitude upstream low-frequency waves can trap the reflected ions at the shock front whe…
Eta Carinae’s 2014.6 Spectroscopic Event: The Extraordinary He II and N II Features
Humphreys, Roberta M.; Davidson, Kris; Mehner, Andrea +2 more
Eta Carinae’s spectroscopic events (periastron passages) in 2003, 2009, and 2014 differed progressively. He ii λ4687 and nearby N ii multiplet 5 have special significance because they respond to very soft X-rays and the ionizing UV radiation field (EUV). Hubble Space Telescope (HST)/STIS observations in 2014 show dramatic increases in both feature…
Hot Plasma from Solar Active Region Cores: a Test of AC and DC Coronal Heating Models?
Schmelz, J. T.; Pathak, S.; Christian, G. M. +2 more
Direct current (DC) models of solar coronal heating invoke magnetic reconnection to convert magnetic free energy into heat, whereas alternating current (AC) models invoke wave dissipation. In both cases the energy is supplied by photospheric footpoint motions. For a given footpoint velocity amplitude, DC models predict lower average heating rates …
Collisionally Excited Filaments in Hubble Space Telescope Hα and Hβ Images of HH 1/2
Bally, J.; Raga, A. C.; Reipurth, B. +2 more
We present new Hα and Hβ images of the HH 1/2 system, and we find that the Hα/Hβ ratio has high values in ridges along the leading edges of the HH 1 bow shock and of the brighter condensations of HH 2. These ridges have Hα/Hβ = 4 → 6, which is consistent with collisional excitation from the n = 1 to the n = 3 and 4 levels of hydrogen in a gas of t…
Suzaku Observation of the Classical Nova V2491 Cyg in Quiescence.
Mukai, K.; Orio, M.; Zemko, P.
We present the Suzaku XIS observation of V2491 Cyg (Nova Cyg 2008 No. 2) obtained in quiescence, more than two years after the outburst. The nova was detected as a very luminous source in a wide spectral range from soft to hard X-rays. A very soft blackbody-like component peaking at 0.5 keV indicates that we observe either remaining, localized hyd…
Dynamics of Rotation in M Dwarfs: Indications for a Change in the Dynamo Regime in Stars at the Onset of Complete Convection
Mullan, D. J.; Houdebine, E. R.
We have measured vsin i with high precision for a sample of dM3 stars (86 targets). We detected rotation in 82 stars (73 dM3 stars and nine dM3e stars). We compare our measurements of vsin i for all of the stars in our dM0, dM2, dM3, and dM4 samples to those from other authors. We find a good agreement down to vsin i values of less than 1 km s
An Embedded Active Nucleus in the OH Megamaser Galaxy IRAS16399-0937
Axon, D. J.; Robinson, A.; Elitzur, M. +7 more
We present a multiwavelength study of the OH megamaser galaxy IRAS16399-0937, based on new Hubble Space Telescope (HST)/Advanced Camera for Surveys F814W and Hα+[N II] images and archive data from HST, Two Micron All Sky Survey, Spitzer, Herschel and the Very Large Array. This system has a double nucleus, whose northern (IRAS16399N) and southern (…
Probing the Physical Properties of z = 4.5 Lyman Alpha Emitters with Spitzer
Finkelstein, Steven L.; Grogin, Norman A.; Tilvi, Vithal +10 more
We present the results from a stellar population modeling analysis of a sample of 162 z = 4.5 and 14 z = 5.7 Lyα emitting galaxies (LAEs) in the Boötes field, using deep Spitzer/IRAC data at 3.6 and 4.5 µm from the Spitzer Lyα Survey, along with Hubble Space Telescope NICMOS and WFC3 imaging at 1.1 and 1.6 µm for a subset of the LAEs. …
The Schmidt Law in Six Galactic Massive Star-forming Regions
Marengo, M.; Smith, H. A.; Allen, L. +3 more
We present a census of young stars in five massive star-forming regions in the 4th Galactic quadrant, G305, G326-4, G326-6, G333 (RCW 106), and G351, and combine this census with an earlier census of young stars in NGC 6334. Each region was observed at J, H, and Ks with the NOAO Extremely Wide-Field Infrared Imager and combined with dee…