Search Publications
On the Importance of the Nonequilibrium Ionization of Si IV and O IV and the Line of Sight in Solar Surges
Martínez-Sykora, J.; Moreno-Insertis, F.; Nóbrega-Siverio, D.
Surges are ubiquitous cool ejections in the solar atmosphere that often appear associated with transient phenomena like UV bursts or coronal jets. Recent observations from the Interface Region Imaging Spectrograph show that surges, although traditionally related to chromospheric lines, can exhibit enhanced emission in Si IV with brighter spectral …
Galaxy Structure, Stellar Populations, and Star Formation Quenching at 0.6 ≲ z ≲ 1.2
Malhotra, Sangeeta; Pasquali, Anna; Joshi, Bhavin +3 more
We use both photometric and spectroscopic data from the Hubble Space Telescope to explore the relationships among 4000 Å break (D4000) strength, colors, stellar masses, and morphology, in a sample of 352 galaxies with log(M */M ⊙) > 9.44 at 0.6 ≲ z ≲ 1.2. We have identified authentically quiescent galaxies in the UVJ diagr…
ALMA Observations toward the Starburst Dwarf Galaxy NGC 5253. I. Molecular Cloud Properties and Scaling Relations
Bendo, George J.; Hirota, Akihiko; Nakanishi, Kouichiro +3 more
We present high-spatial-resolution (∼0.″2, or ∼3 pc) CO(2-1) observations of the nearest young starburst dwarf galaxy, NGC 5253, taken with the Atacama Large Millimeter/submillimeter Array. We have identified 118 molecular clouds with average values of 4.3 pc in radius and 2.2 km s-1 in velocity dispersion, which comprise the molecular …
Using Star Clusters as Tracers of Star Formation and Chemical Evolution: The Chemical Enrichment History of the Large Magellanic Cloud
Chilingarian, Igor V.; Asa'd, Randa
The star formation (SFH) and chemical enrichment (CEH) histories of Local Group galaxies are traditionally studied by analyzing their resolved stellar populations in a form of color-magnitude diagrams obtained with the Hubble Space Telescope. Star clusters can be studied in integrated light using ground-based telescopes to much larger distances. T…
HD 104860 and HD 192758: Two Debris Disks Newly Imaged in Scattered Light with the Hubble Space Telescope
Augereau, J. -C.; Bryden, G.; Mawet, D. +15 more
We present the first scattered-light images of two debris disks around the F8 star HD 104860 and the F0V star HD 192758, respectively ∼45 and ∼67 pc away. We detected these systems in the F110W and F160W filters through our reanalysis of archival Hubble Space Telescope (HST) NICMOS data with modern starlight-subtraction techniques. Our image of HD…
Evidence against Anomalous Compositions for Giants in the Galactic Nuclear Star Cluster
Schultheis, M.; Ryde, N.; Rich, R. M. +5 more
Very strong Sc I lines have recently been found in cool M giants in the Nuclear Star Cluster (NSC) in the Galactic center. Interpreting these as anomalously high scandium abundances in the Galactic center would imply a unique enhancement signature and chemical evolution history for NSCs, and a potential test for models of chemical enrichment in th…
H2CO Ortho-to-para Ratio in the Protoplanetary Disk HD 163296
Öberg, K. I.; Carpenter, J.; Qi, C. +3 more
Ortho-to-para (o/p) ratios of species like water, ammonia, and formaldehyde ({{{H}}}2{CO}) are believed to encode information about the formation history of the molecule. Measurements of o/p ratios in protoplanetary disks could thus be used to constrain their physical and chemical histories. We present the first measurement of the {{{H}…
Balmer-dominated Shocks Exclude Hot Progenitors for Many Type Ia Supernovae
Badenes, C.; Gilfanov, M.; Woods, T. E. +1 more
The evolutionary mechanism underlying Type Ia supernova explosions remains unknown. However, recent efforts to constrain progenitor models based on the influence that their high energy emission would have on the interstellar medium within galaxies have proven successful. For individual remnants, Balmer-dominated shocks reveal the ionization state …
The Progenitor Age and Mass of the Black Hole Formation Candidate N6946-BH1
Dolphin, Andrew E.; Díaz-Rodríguez, Mariangelly; Murphy, Jeremiah W. +3 more
The failed supernova N6946-BH1 likely formed a black hole (BH); we age-date the surrounding population and infer an age and initial mass for the progenitor of this BH formation candidate. First, we use archival Hubble Space Telescope imaging to extract broadband photometry of the resolved stellar populations surrounding this event. Using this phot…
Constraining Gravity at Large Scales with the 2MASS Photometric Redshift Catalog and Planck Lensing
Reichardt, Christian L.; Bianchini, Federico
We present a new measurement of structure growth at z ≃ 0.08 obtained by correlating the cosmic microwave background (CMB) lensing potential map from the Planck satellite with the angular distribution of the 2MASS Photometric Redshift galaxies. After testing for, and finding no evidence for systematic effects, we calculate the angular auto- and cr…