Search Publications
Controlling Influence of Magnetic Field on Solar Wind Outflow: An Investigation using Current Sheet Source Surface Model
Poduval, B.
This Letter presents the results of an investigation into the controlling influence of large-scale magnetic field of the Sun in determining the solar wind outflow using two magnetostatic coronal models: current sheet source surface (CSSS) and potential field source surface. For this, we made use of the Wang and Sheeley inverse correlation between …
Resolving the Fan-spine Reconnection Geometry of a Small-scale Chromospheric Jet Event with the New Solar Telescope
Chen, Bin; Cao, Wenda; Goode, Philip R. +2 more
Jets are ubiquitously present in both quiet and active regions on the Sun. They are widely believed to be driven by magnetic reconnection. A fan-spine structure has been frequently reported in some coronal jets and flares, and has been regarded as a signature of ongoing magnetic reconnection in a topology consisting of a magnetic null connected by…
SOAR Optical and Near-infrared Spectroscopic Survey of Newly Discovered Massive Stars in the Periphery of Galactic Massive Star Clusters I-NGC 3603
Roman-Lopes, A.; Sanmartim, D.; Franco, G. A. P.
In this work, we present the results of a spectroscopic study of very massive stars (VMSs) found outside the center of the massive stellar cluster NGC 3603. From the analysis of the associated Southern Astrophysical Research (SOAR) Telescope spectroscopic data and related optical-near-IR (NIR) photometry, we confirm the existence of several VMSs i…
3C 279 in Outburst in 2015 June: A Broadband SED Study Based on the INTEGRAL Detection
Pian, Elena; Böttcher, Markus; Bottacini, Eugenio +1 more
Blazars radiate from radio through gamma-ray frequencies and thereby make ideal targets for multifrequency studies. Such studies allow the properties of the emitting jet to be constrained. 3C 279 is among the most notable blazars and therefore subject to extensive multifrequency campaigns. We report the results of a campaign ranging from near-IR t…
Globular Clusters and Spur Clusters in NGC 4921, the Brightest Spiral Galaxy in the Coma Cluster
Lee, Myung Gyoon; Jang, In Sung
We resolve a significant fraction of globular clusters (GCs) in NGC 4921, the brightest spiral galaxy in the Coma cluster. We also find a number of extended bright star clusters (star complexes) in the spur region of the arms. The latter are much brighter and bluer than those in the normal star-forming region, being as massive as 3 × 105
Discovery of the Candidate Off-nuclear Ultrasoft Hyper-luminous X-Ray Source 3XMM J141711.1+522541
Romanowsky, Aaron J.; Ramirez-Ruiz, Enrico; Strader, Jay +8 more
We report the discovery of an off-nuclear ultrasoft hyper-luminous X-ray source candidate 3XMM J141711.1+522541 in the inactive S0 galaxy SDSS J141711.07+522540.8 (z = 0.41827, dL = 2.3 Gpc) in the Extended Groth Strip. It is located at a projected offset of ∼1.″0 (5.2 kpc) from the nucleus of the galaxy and was serendipitously detected…
Hubble Space Telescope Proper Motions of Individual Stars in Stellar Streams: Orphan, Sagittarius, Lethe, and the New "Parallel’ Stream"
Anderson, Jay; Law, David R.; van der Marel, Roeland P. +6 more
We present a multi-epoch Hubble Space Telescope (HST) study of stellar proper motions (PMs) for four fields along the Orphan Stream. We determine absolute PMs of several individual stars per target field using established techniques that utilize distant background galaxies to define a stationary reference frame. Five Orphan Stream stars are identi…
Peculiar Velocity Constraints from Five-band SZ Effect Measurements toward RX J1347.5-1145 with MUSIC and Bolocam from the CSO
Czakon, Nicole G.; Glenn, Jason; Zemcov, Michael +25 more
We present Sunyaev-Zel’dovich (SZ) effect measurements from wide-field images toward the galaxy cluster RX J1347.5-1145 obtained from the Caltech Submillimeter Observatory with the Multiwavelength Submillimeter Inductance Camera at 147, 213, 281, and 337 GHz and with Bolocam at 140 GHz. As part of our analysis, we have used higher frequency data f…
Toward a Network of Faint DA White Dwarfs as High-precision Spectrophotometric Standards
Rest, A.; Saha, A.; Stubbs, C. W. +8 more
We present the initial results from a program aimed at establishing a network of hot DA white dwarfs to serve as spectrophotometric standards for present and future wide-field surveys. These stars span the equatorial zone and are faint enough to be conveniently observed throughout the year with large-aperture telescopes. The spectra of these white…
The Relation between [O III]/Hβ and Specific Star Formation Rate in Galaxies at z ∼ 2
van Dokkum, Pieter G.; Franx, Marijn; Leja, Joel +7 more
Recent surveys have identified a seemingly ubiquitous population of galaxies with elevated [O III]/Hβ emission line ratios at z > 1, although the nature of this phenomenon continues to be debated. The [O III]/Hβ line ratio is of interest because it is a main component of the standard diagnostic tools used to differentiate between active galacti…