Search Publications
O VI traces photoionized streams with collisionally ionized boundaries in cosmological simulations of z ∼ 1 massive galaxies
Stern, Jonathan; Dekel, Avishai; Primack, Joel +6 more
We analyse the distribution and origin of O VI in the Circumgalactic Medium (CGM) of dark-matter haloes of ~1012 M⊙ at z ~ 1 in the VELA cosmological zoom-in simulations. We find that the O VI in the inflowing cold streams is primarily photoionized, while in the bulk volume it is primarily collisionally ionized. The photoioni…
The TMRT K band observations towards 26 infrared dark clouds: NH3, CCS, and HC3N
Duan, Yan; Li, Di; Liu, Tie +9 more
We present one of the first Shanghai Tian Ma Radio Telescope (TMRT) K Band observations towards a sample of 26 infrared dark clouds (IRDCs). We observed the (1,1), (2,2), (3,3), and (4,4) transitions of NH3 together with CCS (21–>10) and HC3N J = 2–1, simultaneously. The survey dramatically increases …
Compact Molecular Gas Distribution in Quasar Host Galaxies
Ho, Luis C.; Bauer, Franz E.; Shao, Yali +4 more
We use Atacama Large Millimeter/submillimeter Array CO (2-1) observations of six low-redshift Palomar-Green quasars to study the distribution and kinematics of the molecular gas of their host galaxies at kiloparsec-scale resolution. While the molecular gas content, molecular gas fraction, and star formation rates are similar to those of nearby mas…
Characterizing the Multiphase Origin of [C II] Emission in M101 and NGC 6946 with Velocity-resolved Spectroscopy
Bolatto, Alberto D.; Croxall, Kevin V.; Dale, Daniel A. +10 more
The [C II] fine-structure transition at 158 µm is frequently the brightest far-infrared line in galaxies. Due to its low ionization potential, C+ can trace the ionized, atomic, and molecular phases of the ISM. We present velocity-resolved [C II] and [N II] pointed observations from SOFIA/GREAT on ~500 pc scales in the nearby galax…
Reconstructing solar irradiance from historical Ca II K observations. I. Method and its validation
Solanki, Sami K.; Chatzistergos, Theodosios; Ermolli, Ilaria +5 more
Context. Knowledge of solar irradiance variability is critical to Earth's climate models and understanding the solar influence on Earth's climate. Direct solar irradiance measurements have only been available since 1978. Reconstructions of past variability typically rely on sunspot data. However, sunspot records provide only indirect information o…
The X-Ray Bursts of XTE J1739-285: A NICER Sample
Chakrabarty, Deepto; Arzoumanian, Zaven; Güver, Tolga +10 more
In this work, we report on observations with the Neutron Star Interior Composition Explorer of the known neutron star X-ray transient XTE J1739-285. We observed the source in 2020 February and March, finding it in a highly active bursting state. Across a 20 day period, we detected 32 thermonuclear X-ray bursts, with an average burst recurrence tim…
Multi-spacecraft observations of the structure of the sheath of an interplanetary coronal mass ejection and related energetic ion enhancement
Vainio, R.; Kilpua, E. K. J.; Lavraud, B. +18 more
Context. Sheath regions ahead of coronal mass ejections (CMEs) are large-scale heliospheric structures that form gradually with CME expansion and propagation from the Sun. Turbulent and compressed sheaths could contribute to the acceleration of charged particles in the corona and in interplanetary space, but the relation of their internal structur…
A Kinematic Perspective on the Formation Process of the Stellar Groups in the Rosette Nebula
Lim, Beomdu; Lee, Jeong-Eun; Yun, Hyeong-Sik +6 more
Stellar kinematics is a powerful tool for understanding the formation process of stellar associations. Here, we present a kinematic study of the young stellar population in the Rosette nebula using recent Gaia data and high-resolution spectra. We first isolate member candidates using the published mid-infrared photometric data and the list of X-ra…
Dissecting the Gaia HR diagram within 200 pc
Girardi, Léo; Marigo, Paola; Chen, Yang +6 more
We analyse the high-quality Hertzsprung-Russell diagram (HRD) derived from Gaia data release 2 for the Solar Neighbourhood. We start building an almost complete sample within 200 pc and for |b| > 25○, so as to limit the impact of known errors and artefacts in the Gaia catalogue. Particular effort is then put into improving the modell…
What happened before?. Disks around the precursors of young Herbig Ae/Be stars
Waters, L. B. F. M.; Dominik, C.; Valegård, P. -G.
Context. Planets form in circumstellar disks around pre-main-sequence stars. A key question is, how do the formation and evolution of protoplanetary disks depend on stellar mass? Studies of circumstellar disks at infrared and submillimeter wavelengths around intermediate-mass Herbig Ae/Be stars have revealed disk structures such as cavities, gaps,…