Search Publications
The High-ionization IR Fine Structure Lines as Bolometric Indicators of the AGN Power: Study of the Complete 12 µm AGN Sample
Spinoglio, Luigi; Fernández-Ontiveros, Juan Antonio; Malkan, Matthew A.
The high-ionization mid-IR lines, excited in the narrow-line regions of active galactic nuclei (AGN), barely affected by stellar excitation and dust extinction, trace the AGN bolometric power. We used the complete 12 µm sample of Seyfert galaxies, for which 100/116 objects have reliable 2-10 keV observations. The [Ne V] and [O IV] mid-IR lin…
The Distance and Dynamical History of the Virgo Cluster Ultradiffuse Galaxy VCC 615
Côté, Patrick; Peng, Eric W.; Ferrarese, Laura +6 more
We use deep Hubble Space Telescope imaging to derive a distance to the Virgo Cluster ultradiffuse galaxy (UDG) VCC 615 using the tip of the red giant branch (TRGB) distance estimator. We detect 5023 stars within the galaxy, down to a 50% completeness limit of F814W ≈ 28.0, using counts in the surrounding field to correct for contamination due to b…
HST UV Spectroscopy of the Planet-hosting T Tauri Star PDS 70
Skinner, Stephen L.; Audard, Marc
We summarize Hubble Space Telescope (HST) UV observations of the weak-lined T Tauri star (wTTS) PDS 70 obtained with the Space Telescope Imaging Spectrograph. These observations provide the first far-UV (FUV) and near-UV (NUV) spectra of PDS 70. Ground-based observations have so far revealed two formative giant planets orbiting in a wide gap in it…
Flaring-associated Complex Dynamics in Two M Dwarfs Revealed by Fast, Time-resolved Spectroscopy
Wang, J.; Li, H. L.; Xin, L. P. +11 more
Habitability of an exoplanet is believed to be profoundly affected by activities of the host stars, although the related coronal mass ejections (CMEs) are still rarely detected in solar-like and late-type stars. We here report an observational study on the flares of two M dwarfs triggered by the high-cadence survey performed by the Ground-based Wi…
The Paschen Jump as a Diagnostic of the Diffuse Nebular Continuum Emission in Active Galactic Nuclei
Ho, Luis C.; Brandt, William N.; Barth, Aaron J. +17 more
Photoionization modeling of active galactic nuclei (AGN) predicts that diffuse continuum (DC) emission from the broad-line region makes a substantial contribution to the total continuum emission from ultraviolet through near-infrared wavelengths. Evidence for this DC component is present in the strong Balmer jump feature in AGN spectra, and possib…
A Submillimeter Survey of Faint Galaxies behind 10 Strong Lensing Clusters
Bauer, F. E.; Barger, A. J.; Cowie, L. L. +5 more
We present deep SCUBA-2 450 µm and 850 µm imaging of 10 strong lensing clusters. We provide a >4σ SCUBA-2 850 µm catalog of the 404 sources lying within a radius of $4\buildrel{\,\prime}\over{.} 5$ from the cluster centers. We also provide catalogs of the >4.5σ Atacama Large Millimeter/submillimeter Array (ALMA) 850 µ…
Viewing Angle Observations and Effects of Evolution with Redshift, Black Hole Mass, and Eddington Ratio in Quasar-based Cosmology
Pollo, Agnieszka; Czerny, Bożena; Prince, Raj +2 more
This study is focused on the observational measurement of the viewing angle of individual quasars by modeling the broadband quasar spectrum ranging from the IR to soft X-ray band. Sources are selected from various published catalogs, and their broadband quasi-simultaneous spectral data points were collected and used for modeling. We started with a…
Study of X-Ray Intraday Variability of HBL Blazars Based on Observations Obtained with XMM-Newton
Gupta, Alok C.; Wiita, Paul J.; Jithesh, V. +1 more
We present an extensive study on the X-ray intraday variability of 10 teraelectronvolt-emitting high synchrotron peaked blazars (HBLs): 1ES 0229+200, 1ES 0414+009, PKS 0548-322, 1ES 1101-232, 1H 1219+301, H 1426+428, Mrk 501, 1ES 1959+650, PKS 2005-489, and 1ES 2344+514 made with 25 XMM-Newton pointed observations during its operational period. In…
An 8.56 keV Absorption Line in the Hyperluminous X-Ray Source in NGC 4045: Ultrafast Outflow or Cyclotron Line?
Fürst, Felix; Middleton, Matthew J.; Walton, Dominic J. +5 more
We report on the discovery of an absorption line at $E={8.56}_{-0.11}^{+0.05}$ keV detected with a significance of >3.3σ in the NuSTAR and XMM-Newton spectra of a newly discovered hyperluminous X-ray source (L X > 1041 erg s-1) in the galaxy NGC 4045 at a distance of 32 Mpc. The source was first discovered se…
The Solar Internetwork. III. Unipolar versus Bipolar Flux Appearance
Cheung, M. C. M.; Gošić, M.; Bellot Rubio, L. R. +3 more
Small-scale internetwork (IN) magnetic fields are considered to be the main building blocks of quiet Sun magnetism. For this reason, it is crucial to understand how they appear on the solar surface. Here, we employ a high-resolution, high-sensitivity, long-duration Hinode/NFI magnetogram sequence to analyze the appearance modes and spatiotemporal …