Search Publications
The Origin of the Doppler Flip in HD 100546: A Large-scale Spiral Arm Generated by an Inner Binary Companion
Ginski, Christian; Pinte, Christophe; Rosotti, Giovanni +9 more
Companions at subarcsecond separation from young stars are difficult to image. However, their presence can be inferred from the perturbations they create in the dust and gas of protoplanetary disks. Here we present a new interpretation of SPHERE polarized observations that reveal the previously detected inner spiral in the disk of HD 100546. The s…
Linking Small-scale Solar Wind Properties with Large-scale Coronal Source Regions through Joint Parker Solar Probe-Metis/Solar Orbiter Observations
Telloni, Daniele; Zank, Gary P.; Adhikari, Laxman +92 more
The solar wind measured in situ by Parker Solar Probe in the very inner heliosphere is studied in combination with the remote-sensing observation of the coronal source region provided by the METIS coronagraph aboard Solar Orbiter. The coronal outflows observed near the ecliptic by Metis on 2021 January 17 at 16:30 UT, between 3.5 and 6.3 R ⊙<…
Disconnecting the Dots: Re-examining the Nature of Stellar "Strings" in the Milky Way
Peek, J. E. G.; Zucker, Catherine; Loebman, Sarah
Recent analyses of Gaia data have resulted in the identification of new stellar structures, including a new class of extended stellar filaments called stellar "strings," first proposed by Kounkel & Covey. We explore the spatial, kinematic, and chemical composition of strings to demonstrate that these newfound structures are largely inconsisten…
The X-Ray Luminosity Function Evolution of Quasars and the Correlation between the X-Ray and Ultraviolet Luminosities
Singal, J.; Mutchnick, S.; Petrosian, V.
We explore the evolution of the X-ray luminosity function of quasars and the intrinsic correlation between the X-ray and 2500 Å ultraviolet luminosities, utilizing techniques verified in previous works and a sample of over 4000 quasars detected with Chandra and XMM-Newton in the range 0 < z < 5. We find that quasars have undergone significan…
Deep XMM-Newton Observations of an X-ray Weak Broad Absorption Line Quasar at z = 6.5
Fan, Xiaohui; Keeton, Charles R.; Walter, Fabian +14 more
We report X-ray observations of the most distant known gravitationally lensed quasar, J0439+1634 at z = 6.52, which is also a broad absorption line (BAL) quasar, using the XMM-Newton Observatory. With a 130 ks exposure, the quasar is significantly detected as a point source at the optical position with a total of ${358}_{-19}^{+19}$ net counts usi…
The "Singular" Behavior of the Solar Wind Scaling Features during Parker Solar Probe-BepiColombo Radial Alignment
Richter, Ingo; Auster, Hans-Ulrich; Hadid, Lina Z. +4 more
At the end of 2020 September, the Parker Solar Probe (PSP) and BepiColombo were radially aligned: PSP was orbiting near 0.17 au and BepiColombo near 0.6 au. This geometry is of particular interest for investigating the evolution of solar wind properties at different heliocentric distances by observing the same solar wind plasma parcels. In this wo…
A Partial Filament Eruption in Three Steps Induced by External Magnetic Reconnection
Xu, Zhe; Li, Leping; Zhang, Qingmin +6 more
We present an investigation of partial filament eruption on 2012 June 17 in the active region NOAA 11504. For the first time, we observed the vertical splitting process during the partial eruption with high-resolution narrowband images at 10830 Å. The active filament was rooted in a small δ-sunspot of the active region. Particularly, it underwent …
MARS: A New Maximum-entropy-regularized Strong Lensing Mass Reconstruction Method
Jee, M. James; Cha, Sangjun
Free-form strong-lensing (SL) mass reconstructions typically suffer from overfitting, which manifests itself as false-positive small-scale fluctuations. We present a new free-form MAximum-entropy ReconStruction (MARS) method without the assumption that light traces mass (LTM). The MARS algorithm enables us to achieve excellent convergence in sourc…
The Nascent Milliquasar VT J154843.06+220812.6: Tidal Disruption Event or Extreme Accretion State Change?
Hallinan, Gregg; Graham, Matthew; Lu, Wenbin +5 more
We present a detailed multiwavelength follow-up of the nuclear radio flare VT J154843.06+220812.6, hereafter VT J1548. VT J1548 was selected as a ~1 mJy radio flare in 3 GHz observations from the Very Large Array Sky Survey. It is located in the nucleus of a low-mass ( $\mathrm{log}{M}_{\mathrm{BH}}/{M}_{\odot }\sim 6$ ) host galaxy with weak or n…
A Panchromatic Study of Massive Stars in the Extremely Metal-poor Local Group Dwarf Galaxy Leo A
McQuinn, Kristen B. W.; Williams, Benjamin F.; Choi, Yumi +17 more
We characterize massive stars (M > 8 M ⊙) in the nearby (D ∼ 0.8 Mpc) extremely metal-poor (Z ∼ 5% Z ⊙) galaxy Leo A using Hubble Space Telescope ultraviolet (UV), optical, and near-infrared (NIR) imaging along with Keck/Low-Resolution Imaging Spectrograph and MMT/Binospec optical spectroscopy for 18 main-sequence OB stars…