Search Publications
An interferometric search for SiO maser emission in planetary nebulae
Miranda, Luis F.; Osorio, Mayra; Anglada, Guillem +5 more
Context. Maser emission of SiO, H2O, and OH is widespread in asymptotic giant branch (AGB) stars with oxygen- (O-) rich envelopes. This emission quickly disappears during the post-AGB phase and is extremely rare in planetary nebulae (PNe). So far, only eight PNe have been confirmed to show OH and/or H2O maser emission, and no…
Astrometric Jitter as a Detection Diagnostic for Recoiling and Slingshot Supermassive Black Hole Candidates
Natarajan, Priyamvada; Gezari, Suvi; Ward, Charlotte +4 more
Supermassive black holes (SMBHs) can be ejected from their galactic centers due to gravitational wave recoil or the slingshot mechanism following a galaxy merger. If an ejected SMBH retains its inner accretion disk, it may be visible as an off-nuclear active galactic nucleus (AGN). At present, only a handful of offset AGNs that are recoil or sling…
A Multiwavelength Study of the Symbiotic Mira HM Sge with SOFIA and HST
Goldman, Steven R.; Montiel, Edward; Sankrit, Ravi +3 more
We have targeted the dusty symbiotic Mira system HM Sge with four instruments from the IR to the UV. We have used these observations along with archival observations to study how the system has been evolving after its 1975 nova-like outburst. We have detected rovibrational water emission in a symbiotic system for the first time using new EXES high…
Unveiling gas kinematics and stellar populations in H II regions inside the low-metallicity dwarf nearby galaxy SDSSJ0859 + 3923 with MEGARA at the GTC
Castillo-Morales, A.; Gallego, J.; Mollá, M. +8 more
In this study, we present Integral Field Unit observations of the galaxy SDSSJ0859 + 3923, utilizing the MEGARA (Multi Espectrógrafo en GTC de Alta Resolución para Astronomía) instrument on the GTC (Gran Telescopio Canarias) 10.4m telescope. These observations were conducted in two distinct spectral ranges: 4332-5222 Å and 6097-7345 Å, with a high…
Spectro-temporal Evolution of 4U 1702-429 Using AstroSat-NICER
Misra, Ranjeev; Chattopadhyay, Suchismito; Mandal, Soma +2 more
We present the broadband spectral and timing properties of the atoll source 4U 1702-429 using two observations of AstroSat with the second one having simultaneous NICER data. For both observations, the spectra can be represented by a Comptonizing medium with a blackbody seed photon source that can be identified with the surface of the neutron star…
Li Evolution among Stars of Low/Intermediate Mass: the Metal-deficient Open Cluster NGC 2204
Twarog, Bruce A.; Anthony-Twarog, Barbara J.; Deliyannis, Constantine P. +2 more
We have analyzed high-dispersion spectra in the Li 6708 Å region for 167 stars within the anticenter cluster NGC 2204. From 105 probable members, abundance analysis of 45 evolved stars produces [Fe/H] = ‑0.40 ± 0.12, [Si/Fe] = 0.14 ± 0.12, [Ca/Fe] = 0.29 ± 0.07, and [Ni/Fe] = ‑0.12 ± 0.10, where quoted errors are standard deviations. With E(B ‑ V)…
The PARSEC view of star formation in galaxy centres: from protoclusters to star clusters in an early-type spiral
Bruzual, Gustavo; Burkert, Andreas; Fernández-Ontiveros, Juan A. +2 more
Understanding star formation in galaxies requires resolving the physical scale on which star formation often occurs: the scale of star clusters. We present a multiwavelength, eight-parsec resolution study of star formation in the circumnuclear star cluster and molecular gas rings of the early-type spiral NGC 1386. The cluster ring formed simultane…
Very Long Baseline Array Observations of Parsec-scale Radio Emission in Dual Active Galactic Nuclei
Ho, Luis C.; Zhang, Ming; An, Tao +11 more
It is believed that dual active galactic nuclei (AGN) form during galaxy mergers. Studying dual-AGN emission can provide valuable insights into galaxy merging and evolution. To investigate parsec-scale radio emission properties, we observed eight radio components of four selected dual-AGN systems using the Very Long Baseline Array (VLBA) at 5 GHz …
Study of Plasma Heating Processes in a Coronal Mass Ejection–driven Shock Sheath Region Observed with the Metis Coronagraph
Susino, Roberto; Fineschi, Silvano; Stangalini, Marco +25 more
On 2021 September 28, a C1.6 class flare occurred in active region NOAA 12871, located approximately at 27°S and 51°W on the solar disk with respect to Earth's point of view. This event was followed by a partial halo coronal mass ejection (CME) that caused the deflection of preexisting coronal streamer structures, as observed in visible-light coro…
Fluorine Abundances in Local Stellar Populations
Grisoni, V.; Brady, K. E.; Pilachowski, C. A. +2 more
We present the first fluorine measurements in 12 normal K giants belonging to the Galactic thin and thick disks using spectra obtained with the Phoenix infrared spectrometer on the 2.1 m telescope at Kitt Peak. Abundances are determined from the (1‑0) R9 2.3358 µm feature of the molecule HF. Additionally, sodium abundances are derived in 25 …