Search Publications
A Multiwavelength Study of the Sgr B Region: Contiguous Cloud-Cloud Collisions Triggering Widespread Star Formation Events?
Fukui, Yasuo; Enokiya, Rei
The Sgr B region, including Sgr B1 and Sgr B2, is one of the most active star-forming regions in the Galaxy. Hasegawa et al. originally proposed that Sgr B2 was formed by a cloud-cloud collision (CCC) between two clouds with velocities of ~45 km s-1 and ~75 km s-1. However, some recent observational studies conflict with this…
Call and Response: A Time-resolved Study of Chromospheric Evaporation in a Large Solar Flare
Milligan, Ryan O.; McAteer, R. T. James; Sellers, Sean G.
We studied an X1.6 solar flare produced by NOAA Active Region 12602 on 2014 October 22. The entirety of this event was covered by RHESSI, IRIS, and Hinode/EIS, allowing analysis of the chromospheric response to a nonthermal electron driver. We derived the energy contained in nonthermal electrons via RHESSI spectral fitting and linked the time-depe…
The Effect of Light Deflection by Solar System Objects on High-precision Square Kilometre Array Astrometry
Xu, Ye; Hao, Chaojie; Li, Yingjie +4 more
We have computed the deflection angles caused by 195 objects in the solar system, including 177 satellites, and eight asteroids; 21 satellites and six asteroids can bend light from distant compact extragalactic sources by more than 0.1 µas, and 14 satellites, and the asteroid Ceres can deflect light by more than 1.0 µas. We calculated …
Detection of a Broad 8 µm UIR Feature in the Mid-infrared Spectrum of WR 125 Observed with Subaru/COMICS
Onaka, Takashi; Sakon, Itsuki; Williams, Peredur M. +3 more
We present the detection of a broad 8 µm feature in newly formed dust around the carbon-rich Wolf-Rayet (WC) binary WR 125 from N-band low-resolution (NL; R ~ 250) spectroscopy between 7.3 and 13.6 µm and N-band (11.7 µm) and Q-band (18.8 µm) imaging with Subaru/COMICS in 2019 October. WR 125 is a colliding-wind binary (WC7…
Testing Lyα Emission-line Reconstruction Routines at Multiple Velocities in One System
Redfield, Seth; Drake, Jeremy J.; France, Kevin +6 more
The 1215.67 Å H I Lyα emission line dominates the ultraviolet flux of low-mass stars, including the majority of known exoplanet hosts. Unfortunately, strong attenuation by the interstellar medium (ISM) obscures the line core in most stars, requiring the intrinsic Lyα flux to be reconstructed based on fits to the line wings. We present a test of th…
Direct Far-infrared Metal Abundances (FIRA). I. M101
Smith, J. D.; Groves, B.; Linden, S. T. +12 more
Accurately determining gas-phase metal abundances within galaxies is critical as metals strongly affect the physics of the interstellar medium. To date, the vast majority of widely used gas-phase abundance indicators rely on emission from bright optical lines, whose emissivities are highly sensitive to the electron temperature. Alternatively, dire…
A Molecular Gas Ring Hidden in the Sombrero Galaxy
Fadda, Dario; Sutter, Jessica
We present Herschel, ALMA, and MUSE observations of the molecular ring of Messier 104, also known as the Sombrero galaxy. These previously unpublished archival data shed new light on the content of the interstellar medium of M104. In particular, molecular hydrogen measured by CO emission and dust measured by far-infrared light are uniformly distri…
Unresolved z 8 Point Sources and Their Impact on the Bright End of the Galaxy Luminosity Function
Stiavelli, Massimo; Treu, Tommaso; Trenti, Michele +7 more
The distribution and properties of the first galaxies and quasars are critical pieces of the puzzle in understanding galaxy evolution and cosmic reionization. Previous studies have often excluded unresolved sources as potential low-redshift interlopers. We combine broadband color and photometric redshift analysis with morphological selections to i…
Yellow Post-asymptotic-giant-branch Stars as Standard Candles. I. Calibration of the Luminosity Function in Galactic Globular Clusters
Bond, Howard E.; Ciardullo, Robin; Siegel, Michael H. +1 more
We use the results of a survey for low-surface-gravity stars in Galactic (and LMC) globular clusters to show that "yellow" post-asymptotic-branch (yPAGB) stars are likely to be excellent extragalactic standard candles, capable of producing distances to early-type galaxies that are accurate to a couple of percent. We show that the mean bolometric m…
A 4 kpc Molecular Gas Lane in Cygnus A
Nyland, Kristina; Decarli, Roberto; Perley, Daniel A. +4 more
We present the discovery of a 4 kpc molecular gas lane in the Cygnus A host galaxy, using Atacama Large Millimeter/submillimeter Array CO 2-1 observations. The gas lane is oriented roughly perpendicular to the projected radio jet axis. The CO emission generally follows the clumpy dust lanes seen in Hubble Space Telescope I-band images. The total m…