Search Publications
Snails across Scales: Local and Global Phase-mixing Structures as Probes of the Past and Future Milky Way
Hogg, David W.; Laporte, Chervin F. P.; Price-Whelan, Adrian M. +3 more
Signatures of vertical disequilibrium have been observed across the Milky Way's (MW's) disk. These signatures manifest locally as unmixed phase spirals in z-v z space ("snails-in-phase"), and globally as nonzero mean z and v z , wrapping around the disk into physical spirals in the x-y plane ("snails-in-space"). We explore…
GaiaHub: A Method for Combining Data from the Gaia and Hubble Space Telescopes to Derive Improved Proper Motions for Faint Stars
Anderson, Jay; van der Marel, Roeland P.; Watkins, Laura L. +6 more
We present GAIAHUB, a publicly available tool that combines Gaia measurements with Hubble Space Telescope (HST) archival images to derive proper motions (PMs). It increases the scientific impact of both observatories beyond their individual capabilities. Gaia provides PMs across the whole sky, but the limited mirror size and time baseline restrict…
Methanol Mapping in Cold Cores: Testing Model Predictions
Vasyunin, Anton; Caselli, Paola; Punanova, Anna +5 more
Chemical models predict that in cold cores gas-phase methanol is expected to be abundant at the outer edge of the CO depletion zone, where CO is actively adsorbed. CO adsorption correlates with volume density in cold cores, and, in nearby molecular clouds, catastrophic CO freeze-out happens at volume densities above 104 cm-3.…
Early-time Ultraviolet Spectroscopy and Optical Follow-up Observations of the Type IIP Supernova 2021yja
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Modjaz, Maryam +19 more
We present three epochs of early-time ultraviolet (UV) and optical HST/STIS spectroscopy of the young, nearby Type IIP supernova (SN) 2021yja. We complement the HST data with two earlier epochs of Swift UVOT spectroscopy. The HST and Swift UVOT spectra are consistent with those of other well-studied Type IIP SNe. The UV spectra exhibit rapid cooli…
First Observation of the MeV Gamma-Ray Universe with Bijective Imaging Spectroscopy Using the Electron-tracking Compton Telescope on Board SMILE-2+
Hamaguchi, Kenji; Takada, Atsushi; Kubo, Hidetoshi +12 more
MeV gamma-rays provide a unique window for the direct measurement of line emissions from radioisotopes, but observations have made little significant progress since COMPTEL on board the Compton Gamma-ray Observatory (CGRO). To observe celestial objects in this band, we are developing an electron-tracking Compton camera (ETCC) that realizes both bi…
A 2D Model for Coronal Bright Points: Association with Spicules, UV Bursts, Surges, and EUV Coronal Jets
Moreno-Insertis, F.; Nóbrega-Siverio, D.
Coronal bright points (CBPs) are ubiquitous structures in the solar atmosphere composed of hot small-scale loops observed in extreme-ultraviolet (EUV) or X-rays in the quiet Sun and coronal holes. They are key elements to understanding the heating of the corona; nonetheless, basic questions regarding their heating mechanisms, the chromosphere unde…
The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER). III. The Mass Function of Young Stellar Clusters in M33
Williams, Benjamin F.; Johnson, L. Clifton; Dolphin, Andrew +7 more
We measure the star cluster mass function (CMF) for the Local Group galaxy M33. We use the catalog of stellar clusters selected from the Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region survey. We analyze 711 clusters in M33 with $7.0\lt \mathrm{log}(\mathrm{Age}/\mathrm{yr})\lt 8.5$ , and log(M/M ⊙) > 3.0 as determ…
Evaluating Lyα Emission as a Tracer of the Largest Cosmic Structure at z 2.47
Pentericci, Laura; Hathi, Nimish; Sawicki, Marcin +13 more
The discovery and spectroscopic confirmation of Hyperion, a protosupercluster at z ~ 2.47, provides an unprecedented opportunity to study distant galaxies in the context of their large-scale environment. We carry out deep narrowband imaging of a ≈1° × 1° region around Hyperion and select 157 Lyα emitters (LAEs). The inferred LAE overdensity is δ <…
Quiet Sun Center to Limb Variation of the Linear Polarization Observed by CLASP2 Across the Mg II h and k Lines
Auchère, F.; Kubo, M.; De Pontieu, B. +25 more
The CLASP2 (Chromospheric LAyer Spectro-Polarimeter 2) sounding rocket mission was launched on 2019 April 11. CLASP2 measured the four Stokes parameters of the Mg II h and k spectral region around 2800 Å along a 200″ slit at three locations on the solar disk, achieving the first spatially and spectrally resolved observations of the solar polarizat…
The TREX Survey: Kinematical Complexity Throughout M33's Stellar Disk and Evidence for a Stellar Halo
Williams, Benjamin F.; Gilbert, Karoline M.; Wojno, Jennifer +9 more
We present initial results from a large spectroscopic survey of stars throughout M33's stellar disk. We analyze a sample of 1667 red giant branch (RGB) stars extending to projected distances of ~11 kpc from M33's center (~18 kpc, or ~10 scale lengths, in the plane of the disk). The line-of-sight velocities of RGB stars show the presence of two kin…