Search Publications
Detailed study of the microwave emission of the supernova remnant 3C 396
de Bernardis, P.; Masi, S.; Piacentini, F. +8 more
We have observed the supernova remnant 3C 396 in the microwave region using the Parkes 64-m telescope. Observations have been made at 8.4, 13.5, and 18.6 GHz and in polarization at 21.5 GHz. We have used data from several other observatories, including previously unpublished observations performed by the Green Bank Telescope at 31.2 GHz, to invest…
First Observational Signature of Rotational Deceleration in a Massive, Intermediate-age Star Cluster in the Magellanic Clouds
Deng, Licai; de Grijs, Richard; Li, Chengyuan +1 more
While the extended main-sequence turnoffs (eMSTOs) found in almost all 1-2 Gyr old star clusters in the Magellanic Clouds are often explained by postulating extended star formation histories (SFHs), the tight subgiant branches (SGBs) seen in some clusters challenge this popular scenario. Puzzlingly, the SGB of the eMSTO cluster NGC 419 is signific…
The X-Ray Luminosity Function of M37 and the Evolution of Coronal Activity in Low-mass Stars
Agüeros, Marcel A.; Núñez, Alejandro
We use a 440.5 ks Chandra observation of the ≈500 Myr old open cluster M37 to derive the X-ray luminosity functions of its ≤1.2 {M}⊙ stars. Combining detections of 162 M37 members with upper limits for 160 non-detections, we find that its G, K, and M stars have a similar median (0.5-7 keV) X-ray luminosity {L}{{X}}={10}…
Validation of the Coronal Thick Target Source Model
Xu, Yan; Fleishman, Gregory D.; Gary, Dale E. +1 more
We present detailed 3D modeling of a dense, coronal thick-target X-ray flare using the GX Simulator tool, photospheric magnetic measurements, and microwave imaging and spectroscopy data. The developed model offers a remarkable agreement between the synthesized and observed spectra and images in both X-ray and microwave domains, which validates the…
Gravity field and solar component of the precession rate and nutation coefficients of Comet 67P/Churyumov-Gerasimenko
Souchay, J.; Lhotka, C.; Reimond, S. +1 more
The aim of this study is first to determine the gravity field of the comet 67P/Churyumov-Gerasimenko and second to derive the solar component of the precession rate and nutation coefficients of the spin-axis of the comet nucleus, I.e. without the direct, usually larger, effect of outgassing. The gravity field and related moments of inertia are obt…
The nuclear dust lane of Circinus: collimation without a torus
Tristram, K. R. W.; Prieto, M. A.; Fernández-Ontiveros, J. A. +1 more
In some AGN, nuclear dust lanes connected to kpc-scale dust structures provide all the extinction required to obscure the nucleus, challenging the role of the dusty torus proposed by the Unified Model. In this letter, we show the pc-scale dust and ionized gas maps of Circinus constructed using sub-arcsec-accuracy registration of infrared VLT AO im…
On the accretion process in a high-mass star forming region. A multitransitional THz Herschel-HIFI study of ammonia toward G34.26+0.15
Menten, K. M.; Persson, C. M.; Olberg, M. +8 more
Aims: Our aim is to explore the gas dynamics and the accretion process in the early phase of high-mass star formation.
Methods: The inward motion of molecular gas in the massive star forming region G34.26+0.15 is investigated by using high-resolution profiles of seven transitions of ammonia at THz frequencies observed with Herschel-HIFI.…
The Fate of a Red Nugget: In Situ Star Formation of Satellites around a Massive Compact Galaxy
Morishita, Takahiro; Ichikawa, Takashi
To study the accretion phase for local massive galaxies, we search accreting satellites around a massive compact galaxy ({M}*∼ 3.9× {10}10{M}⊙ ), spectroscopically confirmed ({z}{{spec}}=1.9213) in the eXtreme Deep Field, which has been originally reported in Szomoru et al. We detect 1369 satellite candi…
Coronal Magnetic Fields Derived from Simultaneous Microwave and EUV Observations and Comparison with the Potential Field Model
Shibasaki, Kiyoto; Shiota, Daikou; Nozawa, Satoshi +2 more
We estimated the accuracy of coronal magnetic fields derived from radio observations by comparing them to potential field calculations and the differential emission measure measurements using EUV observations. We derived line-of-sight components of the coronal magnetic field from polarization observations of the thermal bremsstrahlung in the NOAA …
A New Challenge to Solar Dynamo Models from Helioseismic Observations: The Latitudinal Dependence of the Progression of the Solar Cycle
Hill, F.; Jain, K.; Tripathy, S. C. +1 more
The onset of the solar cycle at mid-latitudes, the slowdown in the drift of sunspots toward the equator, the tail-like attachment, and the overlap of successive cycles at the time of minimum activity are delicate issues in models of the αΩ dynamo wave and the flux transport dynamo. Very different parameter values produce similar results, making it…