Search Publications
Star Image Centering with Deep Learning. II. HST/WFPC2 Full Field of View
Casetti-Dinescu, Dana I.; Girard, Terrence M.; Baena-Gallé, Roberto +2 more
We present an expanded and improved deep-learning (DL) methodology for determining centers of star images on Hubble Space Telescope/Wide-Field Planetary Camera 2 (WFPC2) exposures. Previously, we demonstrated that our DL model can eliminate the pixel-phase bias otherwise present in these undersampled images; however that analysis was limited to th…
Enhancing Exoplanet Ephemerides by Leveraging Professional and Citizen Science Data: A Test Case with WASP-77 A b
Dalba, Paul A.; Zellem, Robert T.; Evans, Phil +42 more
We present an updated ephemeris, and physical parameters, for the exoplanet WASP-77 A b. In this effort, we combine 64 ground- and space-based transit observations, 6 space-based eclipse observations, and 32 radial velocity observations to produce this target's most precise orbital solution to date aiding in the planning of James Webb Space Telesc…
Time Variability of FUV Emission from Cool Stars on Multi-year Timescales
France, Kevin; Youngblood, Allison; Kamgar, Leo
The physical and chemical properties of planetary atmospheres are affected by temporal evolution of ultraviolet (UV) radiation inputs from their host stars at all time scales. While studies of X-ray/UV flare properties and long-term stellar evolution of exoplanet host stars have provided new constraints regarding stellar inputs to exoplanetary sys…
SPECtrophotometer for TRansmission Spectroscopy of Exoplanets (SPECTR)
Lee, Byeong-Cheol; Park, Myeong-Gu; Choi, Yeon-Ho +9 more
The SPECtrophotometer for TRansmission spectroscopy of exoplanets (SPECTR) is a new low-resolution optical (3800–6850 Å) spectrophotometer installed at the Bohyunsan Optical Astronomy Observatory 1.8 m telescope. SPECTR is designed for observing the transmission spectra of transiting exoplanets. Unique features of SPECTR are its long slit length o…
Deep Large Binocular Camera r-band Observations of the GOODS-N Field
Fontana, Adriano; Grazian, Andrea; Grogin, Norman A. +22 more
We obtained 838 Sloan r-band images (~28 hr) of the GOODS-North field with the Large Binocular Camera (LBC) on the Large Binocular Telescope in order to study the presence of extended, low surface brightness features in galaxies and investigate the trade-off between image depth and resolution. The individual images were sorted by effective seeing,…
Optical Observations of the Nearby Type Ia Supernova 2021hpr
Zhang, Yu; Zhang, Tianmeng; Wu, Hong +6 more
We present the optical photometric and spectroscopic observations of the nearby Type Ia supernova (SN) 2021hpr. The observations covered the phase of -14.37 to +63.68 days relative to its maximum luminosity in the B band. The evolution of multiband light/color curves of SN 2021hpr is similar to that of normal Type Ia supernovae (SNe Ia) with the e…
Ionization and Star Formation in the Giant H II Region SMC-N66
Kniazev, A.; Hamann, W. -R.; Sabbi, E. +8 more
The NGC 346 young stellar system and associated N66 giant H II region in the Small Magellanic Cloud are the nearest example of a massive star-forming event in a low metallicity (Z ≈ 0.2Z ⊙) galaxy. With an age of ≲3 Myr this system provides a unique opportunity to study relationships between massive stars and their associated H II regio…
The Lyman Alpha Spectral Database (LASD)
Hayes, Matthew; Gronke, Max; Runnholm, Axel
Lymanα (Lyα) emission from star-forming galaxies is an important tool to study a large range of astrophysical questions: it has the potential to carry information about the source galaxy, its nearby circumgalactic medium, and also the surrounding intergalactic medium. Substantial observational and theoretical work has therefore focused on understa…
Proper Plasma Analysis Practice (PPAP), an Integrated Procedure of Extinction Correction and Plasma Diagnostics: A Demo with an HST/WFC3 Image Set of NGC 6720
Ueta, Toshiya; Otsuka, Masaaki
In this work, we propose a proper plasma analysis practice (PPAP), an updated procedure of plasma diagnostics in the era of spatially resolved spectroscopy. In particular, we emphasize the importance of performing both of the extinction correction and the direct method of plasma diagnostics simultaneously as an integrated process. This approach is…
Science Commissioning of NIHTS: The Near-infrared High Throughput Spectrograph on the Lowell Discovery Telescope
Cushing, Michael C.; Gustafsson, Annika; Moskovitz, Nicholas +3 more
The Near-Infrared High Throughput Spectrograph (NIHTS) is in operation on the 4.3 m Lowell Discovery Telescope (LDT) in Happy Jack, AZ. NIHTS is a low-resolution spectrograph (R ∼ 200) that operates from 0.86 to 2.45 microns. NIHTS is fed by a custom dichroic mirror which reflects near-infrared wavelengths to the spectrograph and transmits the vis…