Search Publications
The Source of Leaking Ionizing Photons from Haro11: Clues from HST/COS Spectroscopy of Knots A, B, and C
Cannon, John M.; Hayes, Matthew; Östlin, Göran +15 more
Understanding the escape of ionizing (Lyman continuum) photons from galaxies is vital for determining how galaxies contributed to reionization in the early universe. While directly detecting the Lyman continuum from high-redshift galaxies is impossible due to the intergalactic medium, low-redshift galaxies in principle offer this possibility but r…
Circumstellar Medium Constraints on the Environment of Two Nearby Type Ia Supernovae: SN 2017cbv and SN 2020nlb
Swift, Jonathan J.; Galbany, L.; Brown, P. J. +24 more
We present deep Chandra X-ray observations of two nearby Type Ia supernovae, SN 2017cbv and SN 2020nlb, which reveal no X-ray emission down to a luminosity LX ≲ 5.3 × 1037 and ≲ 5.4 × 1037 erg s-1 (0.3-10 keV), respectively, at ~16-18 days after the explosion. With these limits, we constrain the pre-expl…
Discovery of a Radio Halo (and Relic) in a M500<2×1014 M⊙ Cluster
Di Gennaro, G.; Brunetti, G.; Rossetti, M. +12 more
Radio halos are diffuse synchrotron sources observed in dynamically unrelaxed galaxy clusters. Current observations and models suggest that halos trace turbulent regions in the intracluster medium where mildly relativistic particles are reaccelerated during cluster mergers. Due to the higher luminosities and detection rates with increasing cluster…
Investigating the Nature of MGRO J1908+06 with Multiwavelength Observations
Torres, Diego F.; Li, Jian; Kerr, Matthew +7 more
The unidentified TeV source MGRO J1908+06, with emission extending from hundreds of GeV to beyond 100 TeV, is one of the most intriguing sources in the Galactic plane. MGRO J1908+06 spatially associates with an IceCube hotspot of neutrino emission. Although the hotspot is not significant yet, this suggests a possible hadronic origin of the observe…
Optical Analysis and Modeling of HD96670, a New Black Hole X-Ray Binary Candidate
Gomez, Sebastian; Grindlay, Jonathan E.
We report on optical observations and modeling of HD96670, a single-line spectroscopic binary in the Carina OB2 association. We collected 10 epochs of optical spectroscopy, and optical photometry on 17 nonconsecutive nights on the source. We construct a radial velocity curve from the spectra, and update the orbital period of the binary to be P = 5…
The Relativistic Jet Orientation and Host Galaxy of the Peculiar Blazar PKS 1413+135
Lähteenmäki, A.; Pearson, T. J.; Vedantham, H. K. +26 more
PKS 1413+135 is one of the most peculiar blazars known. Its strange properties led to the hypothesis almost four decades ago that it is gravitationally lensed by a mass concentration associated with an intervening galaxy. It exhibits symmetric achromatic variability, a rare form of variability that has been attributed to gravitational milli-lensin…
Identifying the Coronal Source Regions of Solar Wind Streams from Total Solar Eclipse Observations and in situ Measurements Extending over a Solar Cycle
Johnson, Judd; Habbal, Shadia R.; Druckmüller, Miloslav +7 more
This letter capitalizes on a unique set of total solar eclipse observations acquired between 2006 and 2020 in white light, Fe XI 789.2 nm (Tfexi = 1.2 ± 0.1 MK), and Fe XIV 530.3 nm (Tfexiv = 1.8 ± 0.1 MK) emission complemented by in situ Fe charge state and proton speed measurements from Advanced Composition Explorer/SWEPAM-…
Detection of Flare-associated CME Candidates on Two M-dwarfs by GWAC and Fast, Time-resolved Spectroscopic Follow-ups
Wang, J.; Li, H. L.; Xin, L. P. +8 more
The flare-associated stellar coronal mass ejections (CMEs) of solar-like and late-type stars profoundly impact the habitability of any expolanets in the systems. In this paper, we report the detection of flare-associated CMEs for two M-dwarfs, thanks to a high-cadence survey carried out by the Ground Wide-angle Camera system and fast photometric a…
Resolving Structure in the Debris Disk around HD 206893 with ALMA
Hughes, A. Meredith; Wilner, David J.; Moór, Attila +7 more
Debris disks are tenuous, dusty belts surrounding main-sequence stars generated by collisions between planetesimals. HD 206893 is one of only two stars known to host a directly imaged brown dwarf orbiting interior to its debris ring, in this case at a projected separation of 10.4 au. Here we resolve structure in the debris disk around HD 206893 at…
Multi-wavelength Observations of AT2019wey: a New Candidate Black Hole Low-mass X-ray Binary
Kulkarni, S. R.; Cenko, S. Bradley; Duev, Dmitry A. +21 more
AT2019wey (SRGA J043520.9+552226, SRGE J043523.3+552234) is a transient first reported by the ATLAS optical survey in 2019 December. It rose to prominence upon detection, three months later, by the Spektrum-Roentgen-Gamma (SRG) mission in its first all-sky survey. X-ray observations reported in Yao et al. suggest that AT2019wey is a Galactic low-m…