Search Publications
PHANGS-JWST First Results: The Dust Filament Network of NGC 628 and Its Relation to Star Formation Activity
Sandstrom, Karin M.; Henshaw, Jonathan D.; Kruijssen, J. M. Diederik +36 more
PHANGS-JWST mid-infrared (MIR) imaging of nearby spiral galaxies has revealed ubiquitous filaments of dust emission in intricate detail. We present a pilot study to systematically map the dust filament network (DFN) at multiple scales between 25 and 400 pc in NGC 628. MIRI images at 7.7, 10, 11.3, and 21 µm of NGC 628 are used to generate ma…
Keck Integral-field Spectroscopy of M87 Reveals an Intrinsically Triaxial Galaxy and a Revised Black Hole Mass
Ma, Chung-Pei; Walsh, Jonelle L.; Liepold, Emily R.
The three-dimensional intrinsic shape of a galaxy and the mass of the central supermassive black hole provide key insight into the galaxy's growth history over cosmic time. Standard assumptions of a spherical or axisymmetric shape can be simplistic and can bias the black hole mass inferred from the motions of stars within a galaxy. Here, we presen…
Fractal Aggregates of Submicron-sized Grains in the Young Planet-forming Disk around IM Lup
Ginski, Christian; Tazaki, Ryo; Dominik, Carsten
Despite rapidly growing disk observations, it remains a mystery what primordial dust aggregates look like and what the physical and chemical properties of their constituent grains (monomers) are in young planet-forming disks. Confrontation of models with observations to answer this mystery has been a notorious task because we have to abandon a com…
The Star Formation History of the Milky Way's Nuclear Star Cluster
Lu, Jessica R.; Morris, Mark R.; Ghez, Andrea M. +6 more
We report the first star formation history study of the Milky Ways nuclear star cluster (NSC), which includes observational constraints from a large sample of stellar metallicity measurements. These metallicity measurements were obtained from recent surveys from Gemini and the Very Large Telescope of 770 late-type stars within the central 1.5 pc. …
A Statistical Study of Short-period Decayless Oscillations of Coronal Loops in an Active Region
Long, David M.; Li, Dong
Coronal loop oscillations are common phenomena in the solar corona, which are often classified as decaying and decayless oscillations. Using the high-resolution observation measured by the Extreme Ultraviolet Imager (EUI) on board the Solar Orbiter, we statistically investigate small-scale transverse oscillations with short periods (<200 s) of …
Limit on Supernova Emission in the Brightest Gamma-Ray Burst, GRB 221009A
Carballo-Bello, Julio A.; Smith, Nathan; Wheeler, J. Craig +30 more
We present photometric and spectroscopic observations of the extraordinary gamma-ray burst (GRB) 221009A in search of an associated supernova. Some past GRBs have shown bumps in the optical light curve that coincide with the emergence of supernova spectral features, but we do not detect any significant light-curve features in GRB 221009A, nor do w…
X-Ray Polarization of BL Lacertae in Outburst
Kaaret, Philip; Wu, Kinwah; Enoto, Teruaki +128 more
We report the first >99% confidence detection of X-ray polarization in BL Lacertae. During a recent X-ray/γ-ray outburst, a 287 ks observation (2022 November 27-30) was taken using the Imaging X-ray Polarimetry Explorer (IXPE), together with contemporaneous multiwavelength observations from the Neil Gehrels Swift observatory and XMM-Newton in s…
X-Ray Polarization Observations of BL Lacertae
Wu, Kinwah; Masiero, Joseph R.; Tinyanont, Samaporn +144 more
Blazars are a class of jet-dominated active galactic nuclei with a typical double-humped spectral energy distribution. It is of common consensus that the synchrotron emission is responsible for the low frequency peak, while the origin of the high frequency hump is still debated. The analysis of X-rays and their polarization can provide a valuable …
Mass Models of the Milky Way and Estimation of Its Mass from the Gaia DR3 Data Set
Capuzzo-Dolcetta, Roberto; Sylos Labini, Francesco; Chrobáková, Žofia +1 more
We use data from the Gaia DR3 data set to estimate the mass of the Milky Way (MW) by analyzing the rotation curve in the range of distances 5 to 28 kpc. We consider three mass models: The first model adds a spherical dark matter (DM) halo, following the Navarro-Frenk-White (NFW) profile, to the known stellar components. The second model assumes th…
Early Insights for Atmospheric Retrievals of Exoplanets Using JWST Transit Spectroscopy
Madhusudhan, Nikku; Constantinou, Savvas; Gandhi, Siddharth
We have entered the era of the James Webb Space Telescope (JWST). We use the first JWST transmission spectrum of the hot Saturn-mass exoplanet, WASP-39 b, obtained with the NIRSpec instrument in the 3-5 µm range to investigate (a) what atmospheric constraints are possible with JWST-quality data in this spectral range, (b) requirements for at…