Search Publications
The QuaStar Survey: Detecting Hidden Low-velocity Gas in the Milky Way's Circumgalactic Medium
Werk, Jessica K.; Zheng, Yong; Peek, Joshua +2 more
From our position embedded within the Milky Way's interstellar medium, we have limited ability to detect gas at low relative velocities in the extended Galactic halo because those spectral lines are blended with much stronger signals from dense foreground gas. As a result, the content of the Milky Way's circumgalactic medium (CGM) is poorly constr…
Revealing a New Black Widow Binary 4FGL J0336.0+7502
Kong, Albert K. H.; Li, Kwan-Lok; Jane Yap, Y. X. +1 more
We report on the discovery of a promising candidate for a black widow (BW) millisecond pulsar binary, 4FGL J0336.0+7502, which shows many pulsar-like properties in the 4FGL-DR2 catalog. Within the 95% error region of the LAT source, we identified an optical counterpart with a clear periodicity at Porb = 3.718178(9) hr using the Bohyunsa…
Data-driven Stellar Models
Rix, Hans-Walter; Fouesneau, Morgan; Zucker, Catherine +7 more
We developed a data-driven model to map stellar parameters (Teff, $\mathrm{log}g$ , and $\left[\mathrm{Fe}/{\rm{H}}\right]$ ) accurately and precisely to broadband stellar photometry. This model must, and does, simultaneously constrain the passband-specific dust reddening vector in the Milky Way, R. The model uses a neural network to le…
Ultracool Dwarfs Observed with the Spitzer Infrared Spectrograph. I. An Accurate Look at the L-to-T Transition at 300 Myr from Optical Through Mid-infrared Spectrophotometry
Metchev, Stanimir; Marley, Mark S.; Saumon, Didier +2 more
We present Spitzer IRS 5-14 µm spectra and 16 µm and 22 µm photometry of the T2.5 companion to the ~300 Myr old G0V star HN Peg. We incorporate previous 0.8-5 µm observations to obtain the most comprehensive spectral energy distribution (SED) of an intermediate-gravity L/T-transition dwarf that, together with an accurate Ga…
Peeking Between the Pulses: The Far-UV Spectrum of the Previously Unseen White Dwarf in AR Scorpii
Garnavich, Peter; Littlefield, Colin; Lyutikov, Maxim +1 more
The compact object in the interacting binary AR Sco has widely been presumed to be a rapidly rotating, magnetized white dwarf (WD), but it has never been detected directly. Isolating its spectrum has proven difficult because the spin-down of the WD generates pulsed synchrotron radiation that far outshines the WD's photosphere. As a result, a previ…
A Luminous X-Ray Transient in SDSS J143359.16+400636.0: A Likely Tidal Disruption Event
Riddle, Reed; Stern, Daniel; Gezari, Suvi +9 more
We present the discovery of a luminous X-ray transient, serendipitously detected by Swift's X-ray Telescope on 2020 February 5, located in the nucleus of the galaxy SDSS J143359.16+400636.0 at z = 0.099 (luminosity distance DL = 456 Mpc). The transient was observed to reach a peak luminosity of ∼1044 erg s-1 in the…
FORCAST Imaging of Two Small Nearby Clusters: The Coronet and B 59
Vacca, William D.; Reipurth, Bo; Sandell, Göran +1 more
We present mid-infrared imaging of two young clusters, the Coronet in the CrA cloud core and B 59 in the Pipe Nebula, using the FORCAST camera on the Stratospheric Observatory for Infrared Astronomy. We also analyze Herschel Space Observatory4 PACS and SPIRE images of the associated clouds. The two clusters are at similar, and very clos…
Precise Timing and Phase-resolved Spectroscopy of the Young Pulsar J1617-5055 with NuSTAR
Pavlov, George G.; Kargaltsev, Oleg; Hare, Jeremy +2 more
We report on a Nuclear Spectroscopic Telescope Array (NuSTAR) observation of the young, energetic pulsar PSR J1617-5055. Parkes Observatory 3 GHz radio observations of the pulsar (taken about 7 yr before the NuSTAR observations) are also reported here. NuSTAR detected pulsations at a frequency of f ≈ 14.4 Hz (P ≈ 69.44 ms) and, in addition, the ob…
Energy Budget of Plasma Motions, Heating, and Electron Acceleration in a Three-loop Solar Flare
Kontar, Eduard P.; Fleishman, Gregory D.; Nita, Gelu M. +2 more
Nonpotential magnetic energy promptly released in solar flares is converted to other forms of energy. This may include nonthermal energy of flare-accelerated particles, thermal energy of heated flaring plasma, and kinetic energy of eruptions, jets, upflows/downflows, and stochastic (turbulent) plasma motions. The processes or parameters governing …
The Dynamic Formation of Pseudostreamers
Antiochos, Spiro K.; Scott, Roger B.; Pontin, David I. +2 more
Streamers and pseudostreamers structure the corona at the largest scales, as seen in both eclipse and coronagraph white-light images. Their inverted-goblet appearance encloses broad coronal loops at the Sun and tapers to a narrow radial stalk away from the star. The streamer associated with the global solar dipole magnetic field is long-lived, pre…