Search Publications
APOGEE-2S Discovery of Light- and Heavy-element Abundance Correlations in the Bulge Globular Cluster NGC 6380
Cunha, Katia; Smith, Verne V.; Majewski, Steven R. +11 more
We derive abundance ratios for nine stars in the relatively high-metallicity bulge globular cluster NGC 6380. We find a mean cluster metallicity between [Fe/H] = -0.80 and -0.73, with no clear evidence for a variation in iron abundances beyond the observational errors. Stars with strongly enhanced [N/Fe] abundance ratios populate the cluster and a…
Mrk 1239: a Type-2 Counterpart of Narrow-line Seyfert-1?
Zhou, Hongyan; Ji, Tuo; Shi, Xiheng +10 more
We present new spectrophotometric and spectropolarimetric observations of Mrk 1239, one of the 8 prototypes that defines type-1 narrow-line Seyfert galaxies (NLS1s). Unlike the other typical NLS1s though, a high degree of polarization (P ∼ 5.6%) and red optical-IR (g-W4 = 12.35) colors suggest that Mrk 1239 is more similar to type-2 act…
Detecting Reconnection Sites Using the Lorentz Transformations for Electromagnetic Fields
Lapenta, Giovanni
We take a pragmatic definition of reconnection to find locations where a reconnection electric field causes an E × B drift that carries two components of the magnetic field toward their elimination. With this in mind as our target, we observe that such locations can be found using a new indicator: the velocity of the Lorentz transformation that el…
Near-infrared Studies of Nova V1674 Herculis: A Shocking Record Breaker
Banerjee, D. P. K.; Starrfield, S.; Page, K. L. +3 more
We present near-infrared spectroscopy of Nova Herculis 2021 (V1674 Her), obtained over the first 70 days of its evolution. This fastest nova on record displays a rich emission line spectrum, including strong coronal line emission with complex structures. The hydrogen line fluxes, combined with a distance of ${4.7}_{-1.0}^{+1.3}$ kpc, give an upper…
14 Her: A Likely Case of Planet-Planet Scattering
Gelino, Christopher R.; Faherty, Jacqueline K.; Bardalez Gagliuffi, Daniella C. +4 more
In this Letter, we measure the full orbital architecture of the two-planet system around the nearby K0 dwarf 14 Herculis. 14 Her (HD 145675, HIP 79248) is a middle-aged ( ${4.6}_{-1.3}^{+3.8}$ Gyr) K0 star with two eccentric giant planets identified in the literature from radial velocity (RV) variability and long-term trends. Using archival RV dat…
Sublimation of Laboratory Ices Millimeter/Submillimeter Experiment (SubLIME): Structure-specific Identifications of Products from UV-photolyzed Methanol Ice
Gerakines, P. A.; Milam, S. N.; Widicus Weaver, S. L. +1 more
Submillimeter/far-IR spectroscopy was used to detect and quantify organic molecules sublimated after the ultraviolet photolysis (at 12 K) and warm-up (up to 300 K) of a methanol (CH3OH) ice sample. Eleven sublimated photoproducts were uniquely identified: carbon monoxide (CO), formaldehyde (H2CO), ketene (C2H2…
HO Puppis: Not a Be Star, but a Newly Confirmed IW And-type Star
Duev, Dmitry A.; Riddle, Reed; Mróz, Przemek +19 more
HO Puppis (HO Pup) was considered as a Be-star candidate based on its γ Cassiopeiae-type light curve, but lacked spectroscopic confirmation. Using distance measured from Gaia Data Release 2 and the spectral-energy-distribution fit on broadband photometry, the Be-star nature of HO Pup is ruled out. Furthermore, based on the 28,700 photometric data …
The Nature of HI-absorption-selected Galaxies at z ≈ 4
Prochaska, J. X.; Revalski, M.; Rafelski, M. +3 more
We report a Karl G. Jansky Very Large Array (JVLA) search for redshifted CO(1-0) or CO(2-1) emission, and a Hubble Space Telescope Wide Field Camera 3 (HST-WFC3) search for rest-frame near-ultraviolet (NUV) stellar emission, from seven HI-selected galaxies associated with high-metallicity ([M/H] ≥ -1.3) damped Lyα absorbers (DLAs) at z ≈ 4. The ga…
The First Extensive Exploration of UV-bright Stars in the Globular Cluster NGC 2808
Sahu, Snehalata; Subramaniam, Annapurni; Prabhu, Deepthi S.
In this study, we identified and characterized the hot and luminous UV-bright stars in the globular cluster NGC 2808. We combined data from the Ultra Violet Imaging Telescope (UVIT) on board the Indian space satellite AstroSat with the Hubble Space Telescope UV Globular Cluster Survey data for the central region (within $\sim 2\buildrel{\,\prime}\…
Optical Identification and Spectroscopy of Supernova Remnants in the Galaxy M51
Blair, William P.; Long, Knox S.; Winkler, P. Frank +2 more
Using a combination of ground-based and Hubble Space Telescope imaging, we have constructed a catalog of 179 supernova remnants (SNRs) and SNR candidates in the nearby spiral galaxy M51. Follow-up spectroscopy of 66 of the candidates confirms that 61 of these are SNRs and suggests that the vast majority of the unobserved objects are SNRs as well. …