Search Publications
Interpreting the Statistical Properties of High-z Extragalactic Sources Detected by the South Pole Telescope Survey
Cai, Zhen-Yi; Negrello, Mattia; De Zotti, Gianfranco
The results of the recently published spectroscopically complete survey of dusty star-forming galaxies detected by the South Pole Telescope over 2500 deg2 proved to be challenging for galaxy formation models that generally underpredict the observed abundance of high-z galaxies. In this paper we interpret these results in the light of a …
The Color Gradients of the Globular Cluster Systems in M87 and M49
Liu, Chengze; Côté, Patrick; Peng, Eric W. +8 more
Combining data from the ACS Virgo Cluster Survey and the Next Generation Virgo cluster Survey, we extend previous studies of color gradients of the globular cluster (GC) systems of the two most massive galaxies in the Virgo cluster, M87 and M49, to radii of ~15 R e (~200 kpc for M87 and ~250 kpc for M49, where R e is the ef…
Follow-up of Young Stars Identified with BANYAN Σ: New Low-mass Members of Nearby Moving Groups
Johns-Krull, Christopher M.; Flagg, L.; Stahl, Asa G.
The characterization of moving groups offers a powerful means to identify large populations of young stars. In this paper, we present a sample of follow-up observations for 56 systems that have previously been proposed as members of young stellar associations through the application of the BANYAN Σ kinematic classification tool. Our measurements, …
Extremely Slow (V sw < 300 km s-1) Solar Winds (ESSWs) at 1 au: Causes of Extreme Geomagnetic Quiet at Earth
Hajra, Rajkumar; Tsurutani, Bruce T.
A search for extremely slow (V sw < 300 km s-1) solar winds (ESSWs) at 1 au has been conducted using hourly average solar wind data from 1963 through 2021. 297 ESSW events were identified with an average duration of ~2.0 ± 1.4 days. The lowest speed detected was 156 km s-1. Ten of the lowest-speed events were an…
Investigation of the Timing and Spectral Properties of an Ultraluminous X-Ray Pulsar NGC 7793 P13
Hu, Chin-Ping; Kong, A. K. H.; Hui, C. Y. +3 more
We perform both timing and spectral analyses using the archival X-ray data taken with Swift, XMM-Newton, NICER, and NuSTAR from 2016 to 2020 to study an ultraluminous pulsar, NGC 7793 P13, that showed a long period of super-Eddington accretion. We use the Rayleigh test to investigate the pulsation at different epochs, and confirm the variation of …
Sequential Star Formation in the Young SMC Region NGC 602: Insights from ALMA
Bolatto, Alberto D.; Meixner, Margaret; Sabbi, Elena +7 more
NGC 602 is a young, low-metallicity star cluster in the "Wing" of the Small Magellanic Cloud. We reveal the recent evolutionary past of the cluster through analysis of high-resolution (~0.4 pc) Atacama Large Millimeter/submillimeter Array observations of molecular gas in the associated H II region N90. We identify 110 molecular clumps (R < 0.8 …
Spatially Resolved X-Ray Study of Supernova Remnant G306.3-0.9 with Unusually High Calcium Abundance
Toonen, Silvia; Nomoto, Ken'ichi; Vink, Jacco +6 more
G306.3-0.9 is an asymmetric Galactic supernova remnant (SNR), whose progenitor has been thought to be a Type Ia supernova (SN), but its high Ca abundance appears inconsistent with the Type Ia origin. Hoping to uncover the reason for its asymmetry and the origin of this SNR, we performed a spatially resolved X-ray spectroscopic analysis of XMM-Newt…
Search for Hα Emitters at z 7.8: A Constraint on the Hα-based Star Formation Rate Density
Asada, Yoshihisa; Ohta, Kouji
We search for Hα emitters at z ~ 7.8 in four gravitationally lensed fields observed in the Hubble Frontier Fields program. We use the Lyman break method to select galaxies at the target redshift and perform photometry in the Spitzer/IRAC 5.8 µm band to detect Hα emission from the candidate galaxies. We find no significant detections of count…
Polarization Observations of a Split-band Type II Radio Burst from the Solar Corona
Ramesh, R.; Kathiravan, C.
Using temporal observations of circular polarized harmonic plasma emission from a split-band type II solar radio burst at 80 MHz, we separately estimated the coronal magnetic field strengths (B) associated with the lower (L) and upper (U) frequency bands of the burst. The corresponding Stokes I and V data were obtained with the polarimeter operati…
Distances to Local Group Galaxies via Population II, Stellar Distance Indicators. I. The Sculptor Dwarf Spheroidal
Madore, Barry F.; Freedman, Wendy L.; Cerny, William +5 more
We determine the distance to the Sculptor Dwarf Spheroidal via three Population II stellar distance indicators: (a) the Tip of the Red Giant Branch (TRGB), (b) RR Lyrae variables (RRLs), and (c) the ridgeline of the blue horizontal branch (HB). High signal-to-noise, wide-field VI imaging that covers an area $48^{\prime} \,\times \,48^{\prime} $ an…