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Spectroscopic Confirmation of the Sixth Globular Cluster in the Fornax Dwarf Spheroidal Galaxy
Caldwell, Nelson; Mateo, Mario; Bailey, John I., III +5 more
The Fornax dwarf spheroidal galaxy has an anomalous number of globular clusters, five, for its stellar mass. There is a longstanding debate about a potential sixth globular cluster (Fornax 6) that has recently been "rediscovered" in DECam imaging. We present new Magellan/M2FS spectroscopy of the Fornax 6 cluster and Fornax dSph. Combined with lite…
Extragalactic Magnetism with SOFIA (Legacy Program) - II: A Magnetically Driven Flow in the Starburst Ring of NGC 1097
Beckman, John E.; Hughes, Annie; Dale, Daniel +9 more
Galactic bars are frequent in disk galaxies and they may support the transfer of matter toward the central engine of active nuclei. The barred galaxy NGC 1097 has magnetic forces controlling the gas flow at several kpc scales, which suggest that magnetic fields (B-fields) are dynamically important along the bar and nuclear ring. However, the effec…
Stratigraphic Relationships in Jezero Crater, Mars: Constraints on the Timing of Fluvial-Lacustrine Activity From Orbital Observations
Hauber, E.; Gupta, S.; Quantin-Nataf, C. +15 more
On February 18, 2021 NASA's Perseverance rover landed in Jezero crater, located at the northwestern edge of the Isidis basin on Mars. The uppermost surface of the present-day crater floor is dominated by a distinct geologic assemblage previously referred to as the dark-toned floor. It consists of a smooth, dark-toned unit overlying and variably co…
Towards a more complete sample of binary central stars of planetary nebulae with Gaia
Rejkuba, M.; Walton, N. A.; Chornay, N. +3 more
Context. Many if not most planetary nebulae (PNe) are now thought to be the outcome of binary evolutionary scenarios. However, only a few percent of the PNe in the Milky Way are known to host binary systems. The high-precision repeated observing and long time baseline of Gaia make it well suited for detecting new close binaries through photometric…
O VI traces photoionized streams with collisionally ionized boundaries in cosmological simulations of z ∼ 1 massive galaxies
Stern, Jonathan; Dekel, Avishai; Primack, Joel +6 more
We analyse the distribution and origin of O VI in the Circumgalactic Medium (CGM) of dark-matter haloes of ~1012 M⊙ at z ~ 1 in the VELA cosmological zoom-in simulations. We find that the O VI in the inflowing cold streams is primarily photoionized, while in the bulk volume it is primarily collisionally ionized. The photoioni…
The TMRT K band observations towards 26 infrared dark clouds: NH3, CCS, and HC3N
Duan, Yan; Li, Di; Liu, Tie +9 more
We present one of the first Shanghai Tian Ma Radio Telescope (TMRT) K Band observations towards a sample of 26 infrared dark clouds (IRDCs). We observed the (1,1), (2,2), (3,3), and (4,4) transitions of NH3 together with CCS (21–>10) and HC3N J = 2–1, simultaneously. The survey dramatically increases …
Compact Molecular Gas Distribution in Quasar Host Galaxies
Ho, Luis C.; Bauer, Franz E.; Shao, Yali +4 more
We use Atacama Large Millimeter/submillimeter Array CO (2-1) observations of six low-redshift Palomar-Green quasars to study the distribution and kinematics of the molecular gas of their host galaxies at kiloparsec-scale resolution. While the molecular gas content, molecular gas fraction, and star formation rates are similar to those of nearby mas…
Characterizing the Multiphase Origin of [C II] Emission in M101 and NGC 6946 with Velocity-resolved Spectroscopy
Bolatto, Alberto D.; Croxall, Kevin V.; Dale, Daniel A. +10 more
The [C II] fine-structure transition at 158 µm is frequently the brightest far-infrared line in galaxies. Due to its low ionization potential, C+ can trace the ionized, atomic, and molecular phases of the ISM. We present velocity-resolved [C II] and [N II] pointed observations from SOFIA/GREAT on ~500 pc scales in the nearby galax…
Reconstructing solar irradiance from historical Ca II K observations. I. Method and its validation
Solanki, Sami K.; Chatzistergos, Theodosios; Ermolli, Ilaria +5 more
Context. Knowledge of solar irradiance variability is critical to Earth's climate models and understanding the solar influence on Earth's climate. Direct solar irradiance measurements have only been available since 1978. Reconstructions of past variability typically rely on sunspot data. However, sunspot records provide only indirect information o…
The X-Ray Bursts of XTE J1739-285: A NICER Sample
Chakrabarty, Deepto; Arzoumanian, Zaven; Güver, Tolga +10 more
In this work, we report on observations with the Neutron Star Interior Composition Explorer of the known neutron star X-ray transient XTE J1739-285. We observed the source in 2020 February and March, finding it in a highly active bursting state. Across a 20 day period, we detected 32 thermonuclear X-ray bursts, with an average burst recurrence tim…