Search Publications
Discovery of a Highly Collimated Flow from the High-mass Protostar ISOSS J23053+5953 SMM2
Zhang, Qizhou; Carrasco-González, Carlos; Linz, Hendrik +6 more
We present Very Large Array C-, X-, and Q-band continuum observations, as well as 1.3 mm continuum and CO(2-1) observations with the Submillimeter Array toward the high-mass protostellar candidate ISOSS J23053+5953 SMM2. Compact centimeter continuum emission was detected near the center of the SMM2 core with a spectral index of 0.24(± 0.15) betwee…
ALMA View of the ρ Ophiuchi A PDR with a 360 au Beam: The [C I] Emission Originates from the Plane-parallel PDR and Extended Gas
Nakamura, Fumitaka; Shimajiri, Yoshito; Yamagishi, Mitsuyoshi +5 more
We present the results of data analysis of the [C I] (3P1-3P0) emission from the ρ Ophiuchi A photon-dominated region (PDR) obtained in the ALMA ACA standalone mode with a spatial resolution of 2.6 arcsec (360 au). The [C I] emission shows filamentary structures with a width of ∼1000 au, which are adjace…
Do MURaM and STAGGER Simulations of Solar Faculae Match Observational Signatures from Magnetic Structures?
Cubas Armas, Melania; Fabbian, Damian
We compare results of simulations of solar facular-like conditions performed using the numerical codes MURaM and STAGGER. Both simulation sets have a similar setup, including the initial condition of ≈200 G vertical magnetic flux. After interpolating the output physical quantities to constant optical depth, we compare them and test them against in…
X-Ray Sources in the 1.75 Ms Ultra Narrow Deep Field Observed by XMM-Newton
Vignali, C.; Nicastro, F.; Krongold, Y. +5 more
In this work, we present the results of the survey carried out on one of the deepest X-ray fields observed by the XMM-Newton satellite. The 1.75 Ms Ultra Narrow Deep Field (XMM175UNDF) survey is made by 13 observations taken over 2 yr with a total exposure time of 1.75 Ms (1.372 Ms after flare-filtered) in a field of 30' × 30' centered around the …
Evidence of Solar-cycle-related Structural Changes in the Solar Convection Zone
Basu, Sarbani
While it has been relatively easy to determine solar-cycle related changes in solar dynamics, determining changes in structure in the deeper layers of the Sun has proved to be difficult. By using helioseismic data obtained over two solar cycles, and sacrificing resolution in favor of lower uncertainties, we show that there are significant changes …
Automated Photometry of γ Cassiopeiae: The Last Roundup
Smith, M. A.; Henry, G. W.
γ Cassiopeiae (B0.5IVe) is the noted prototype of a subgroup of classical Be stars exhibiting hard thermal X-ray emission. This paper reports results from a 23 yr optical campaign on this star with an automated photometric telescope (APT). A series of unstable long cycles of length 56-91 days has nearly ceased over the last decade. Also, we revise…
The First Radio Spectrum of a Rapidly Rotating A-type Star
De la Luz, V.; Moór, A.; Fehér, O. +9 more
The radio spectra of main-sequence stars remain largely unconstrained due to the lack of observational data to inform stellar atmosphere models. As such, the dominant emission mechanisms at long wavelengths, how they vary with spectral type, and how much they contribute to the expected brightness at a given radio wavelength are still relatively un…
Evidence for Cold Plasma in Planetary Nebulae From Radio Observations With the LOw Frequency ARray (LOFAR)
White, Glenn J.; Haverkorn, Marijke; Shimwell, Timothy +6 more
We present observations of planetary nebulae with the LOw Frequency ARray (LOFAR) between 120 and 168 MHz. The images show thermal free-free emission from the nebular shells. We have determined the electron temperatures for spatially resolved, optically thick nebulae. These temperatures are 20%-60% lower than those estimated from collisionally exc…
Mapping Milky Way Halo Substructure Using Stars in the Extended Blue Tail of the Horizontal Branch
Newberg, Heidi Jo; Gryncewicz, Robert; Martin, Charles +2 more
Although blue horizontal branch (BHB) stars are commonly used to trace halo substructure, the stars bluer than (g - r) < -0.3 are ignored owing to the difficulty in determining their absolute magnitudes. The blue extension of the horizontal branch (HBX) includes BHB tail stars and extreme horizontal branch (EHB) stars. We present a method for i…
Radio Proper Motions of the Energetic Pulsar PSR J1813-1749
Rodríguez, Luis F.; Dzib, Sergio A.
PSR J1813-1749 has peculiarities that make it a very interesting object of study. It is one of the most energetic and the most scattered pulsars known. It is associated with HESS J1813-178, one of the brightest and most compact TeV sources in the sky. Recently, Ho et al. used archival X-ray Chandra observations separated by more than 10 yr and det…