Search Publications
Identification of pre-stellar cores in high-mass star forming clumps via H2D+ observations with ALMA
Wyrowski, F.; Caselli, P.; Giannetti, A. +5 more
Context. The different theoretical models concerning the formation of high-mass stars make distinct predictions regarding their progenitors, which are the high-mass pre-stellar cores. However, no conclusive observation of such objects has been made to date.
Aims: We aim to study the very early stages of high-mass star formation in two infrare…
Eclipsing the X-Ray Emitting Region in the Active Galaxy NGC 6814
Miller, Jon M.; Gallo, Luigi C.; Gonzalez, Adam G.
We report the detection of a rapid occultation event in the nearby Seyfert galaxy NGC 6814, simultaneously captured in a transient light curve and spectral variability. The intensity and hardness ratio curves capture distinct ingress and egress periods that are symmetric in duration. Independent of the selected continuum model, the changes can be …
The properties of dwarf spheroidal galaxies in the Cen A group. Stellar populations, internal dynamics, and a heart-shaped Hα ring
Coccato, Lodovico; Fahrion, Katja; Müller, Oliver +7 more
Dwarf spheroidal galaxies (dSphs) have been extensively investigated in the Local Group, but their low luminosity and surface brightness make similar work in more distant galaxy groups challenging. Modern instrumentation unlocks the possibility of scrutinizing these faint systems in other environments, expanding the parameter space of group proper…
ALMA 870 µm continuum observations of HD 100546. Evidence of a giant planet on a wide orbit
Lodato, G.; Fedele, D.; Maud, L. +1 more
This paper reports on a new analysis of archival ALMA 870 µm dust continuum observations. Along with the previously observed bright inner ring (r ~ 20-40 au), two addition substructures are evident in the new continuum image: a wide dust gap, r ~ 40-150 au, and a faint outer ring ranging from r ~ 150 au to r ~ 250 au and whose presence was f…
Enhanced Localization of Transients Based on a Novel Cross-correlation Method
Huang, Y.; Zhang, S. N.; Zhao, Y. +12 more
Locating gamma-ray transients including gamma-ray bursts (GRBs) and soft gamma repeater (SGR) bursts is of great importance in multi-messenger and multi-wavelength astronomy, such as guiding optical and radio follow-up observations and evaluating the association of a GRB with a gravitational wave or an SGR with a galaxy or fast radio burst (FRB). …
Fundamental X-ray corona parameters of Swift/BAT AGN
Mushotzky, Richard; Hinkle, Jason T.
While X-ray emission from active galactic nuclei (AGN) is common, the detailed physics behind this emission is not well understood. This is in part because high quality broad-band spectra are required to precisely derive fundamental parameters of X-ray emission, such as the photon index, folding energy, and reflection coefficient. Here, we present…
Photometric cross-calibration of the SDSS Stripe 82 Standard Stars catalogue with Gaia EDR3, and comparison with Pan-STARRS1, DES, CFIS, and GALEX catalogues
Gwyn, Stephen; Ivezić, Željko; Tucker, Douglas L. +3 more
We extend the SDSS Stripe 82 Standard Stars catalogue with post-2007 SDSS imaging data. This improved version lists averaged SDSS ugriz photometry for nearly a million stars brighter than r ~ 22 mag. With 2-3 times more measurements per star, random errors are 1.4-1.7 times smaller than in the original catalogue, and about three times smaller than…
Systematic Study of Acceleration Efficiency in Young Supernova Remnants with Nonthermal X-Ray Observations
Uchiyama, Yasunobu; Aharonian, Felix; Khangulyan, Dmitry +1 more
Cutoff energy in a synchrotron radiation spectrum of a supernova remnant (SNR) contains a key parameter of ongoing particle acceleration. We systematically analyze 11 young SNRs, including all historical SNRs, to measure the cutoff energy, thus shedding light on the nature of particle acceleration at the early stage of SNR evolution. The nontherma…
Signature of the turbulent component of the solar dynamo on active region scales and its association with flaring activity
Abramenko, Valentina I.
It is a challenging problem to obtain observational evidence of the turbulent component of solar dynamo operating in the convective zone because the dynamo action is hidden below the photosphere. Here we present results of a statistical study of flaring active regions (ARs) that produced strong solar flares of an X-ray class X1.0 and higher during…
The Remnant and Origin of the Historical Supernova 1181 AD
Parker, Quentin A.; Ritter, Andreas; Guerrero, Martín A. +3 more
The guest star of AD 1181 is the only historical supernova of the past millennium that is without a definite counterpart. The previously proposed association with supernova remnant G130.7+3.1 (3C 58) is in strong doubt because of the inferred age of this remnant. Here we report a new identification of SN 1181 with our codiscovery of the hottest kn…