Search Publications
Origin of Quasi-periodic Pulsation at the Base of a Kink-unstable Jet
Srivastava, A. K.; Kayshap, Pradeep; Rajaguru, S. P. +3 more
We studied a blowout jet that occurred at the west limb of the Sun on 2014 August 29 using high-resolution imaging/spectroscopic observations provided by the Solar Dynamics Observatory/Atmospheric Imaging Assembly and the Interface Region Imaging Spectrograph. An inverse γ-shaped flux rope appeared before the jet-morphological indication of the on…
Green Bank Telescope Discovery of the Redback Binary Millisecond Pulsar PSR J0212+5321
Perez, Karen I.; Bogdanov, Slavko; Halpern, Jules P. +1 more
We report the discovery of a 2.11 ms binary millisecond pulsar during a targeted search of the redback optical candidate coincident with the γ-ray source 3FGL J0212.5+5320 using the Robert C. Byrd Green Bank Telescope (GBT) with the Breakthrough Listen backend at L band. Over a seven month period, five pointings were made near inferior conjunction…
ALMA High-frequency Long Baseline Campaign in 2021: Highest Angular Resolution Submillimeter Wave Images for the Carbon-rich Star R Lep
Hirota, Akihiko; Hales, Antonio S.; Takahashi, Satoko +11 more
The Atacama Large Millimeter/submillimeter Array (ALMA) was used in 2021 to image the carbon-rich evolved star R Lep in Bands 8-10 (397-908 GHz) with baselines up to 16 km. The goal was to validate the calibration, using band-to-band (B2B) phase referencing with a close phase calibrator J0504-1512, 1.°2 from R Lep in this case, and the imaging pro…
ALMA 1.1 mm Observations of a Conservative Sample of High-redshift Massive Quiescent Galaxies in SHELA
Papovich, Casey; Finkelstein, Steven L.; Bagley, Micaela B. +11 more
We present a sample of 30 massive (log(M */M ⊙) > 11) z = 3-5 quiescent galaxies selected from the Spitzer-HETDEX Exploratory Large Area (SHELA) Survey and observed at 1.1 mm with Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 observations. These ALMA observations would detect even modest levels of dust-obscure…
Discovery of the Exceptionally Short Period Ultracool Dwarf Binary LP 413-53AB
Burgasser, Adam J.; Hsu, Chih-Chun; Theissen, Christopher A.
We report the detection of large-amplitude, rapid radial velocity (RV) variations and line-splitting in high-resolution Keck/NIRSPEC spectra of the M9 dwarf LP 413-53. We attribute these features to binary motion. Analyzing data spanning 15 yr, we infer a preliminary orbital period of 0.7106156 ± 0.0000002 days, an eccentricity of 0.0088 ± 0.0017,…
The Metallicity and Distance of Leo A from Blue Supergiants
Bresolin, Fabio; Kudritzki, Rolf-Peter; Urbaneja, Miguel A.
We have obtained high-quality spectra of blue supergiant candidates in the dwarf irregular galaxy Leo A with the Low Resolution Imaging Spectrometer at the Keck I telescope. From the quantitative analysis of seven B8-A0 stars, we derive a mean metallicity [Z] = -1.35 ± 0.08, in excellent agreement with the gas-phase chemical abundance. From the st…
Understanding the Relationship between Solar Coronal Abundances and F10.7 cm Radio Emission
Long, David M.; Brooks, David H.; Baker, Deborah +7 more
Sun-as-a-star coronal plasma composition, derived from full-Sun spectra, and the F10.7 radio flux (2.8 GHz) have been shown to be highly correlated (r = 0.88) during solar cycle 24. However, this correlation becomes nonlinear during increased solar magnetic activity. Here we use cotemporal, high spatial resolution, multiwavelength images of the Su…
Infrared Ejecta and Cold Dust in the Young Supernova Remnant N132D
Slavin, Jonathan D.; Rho, Jeonghee; Ravi, Aravind P. +1 more
We present Spitzer, Wide-field Infrared Survey Explorer (WISE), and Herschel observations of the young supernova remnant (SNR) N132D in the Large Magellanic Cloud, including 3-40 µm Spitzer Infrared Spectrograph (IRS) mapping, 12 µm WISE and 70, 100, 160, 250, 350, and 500 µm Herschel images. The high-velocity lines of [Ne II] at…
Delayed Development of Cool Plasmas in X-Ray Flares from the Young Sun-like Star κ 1 Ceti
Hamaguchi, Kenji; Toriumi, Shin; Arzoumanian, Zaven +3 more
The Neutron star Interior Composition Explorer (NICER) X-ray observatory observed two powerful X-ray flares equivalent to superflares from the nearby young solar-like star κ 1 Ceti in 2019. NICER follows each flare from the onset through the early decay, collecting over 30 counts s-1 near the peak, enabling a detailed spectra…
The Masses of Supernova Remnant Progenitors in M33
Williams, Benjamin F.; Dolphin, Andrew; Dalcanton, Julianne J. +7 more
Using resolved optical stellar photometry from the Panchromatic Hubble Andromeda Treasury Triangulum Extended Region survey, we measured the star formation history near the position of 85 supernova remnants (SNRs) in M33. We constrained the progenitor masses for 60 of these SNRs, finding that the remaining 25 remnants had no local star formation i…