Search Publications
Massive stars in the Sagittarius Dwarf Irregular Galaxy
Garcia, Miriam
Low metallicity massive stars hold the key to interpret numerous processes in the past Universe including re-ionization, starburst galaxies, high-redshift supernovae, and γ-ray bursts. The Sagittarius Dwarf Irregular Galaxy [SagDIG, 12+log(O/H) = 7.37] represents an important landmark in the quest for analogues accessible with 10-m class telescope…
Disentangling the complex broad-band X-ray spectrum of IRAS 13197-1627 with NuSTAR, XMM-Newton and Suzaku
Harrison, F. A.; Stern, D.; Fabian, A. C. +8 more
We present results from a coordinated XMM-Newton+NuSTAR observation of the type 1.8 Seyfert galaxy IRAS 13197-1627. This is a highly complex source, with strong contributions from relativistic reflection from the inner accretion disc, neutral absorption and further reprocessing by more distant material, and ionized absorption from an outflow. We u…
A UV-to-NIR Study of Molecular Gas in the Dust Cavity around RY Lupi
France, K.; Alcalá, J. M.; Williams, J. P. +10 more
We present a study of molecular gas in the inner disk (r< 20 {au}) around RY Lupi, with spectra from HST-COS, HST-STIS, and VLT-CRIRES. We model the radial distribution of flux from hot gas in a surface layer between r = 0.1-10 au, as traced by Lyα-pumped H2. The result shows H2 emission originating in a ring centered at ∼…
Molecular gas in the northern nucleus of Mrk 273: Physical and chemical properties of the disc and its outflow
Krips, M.; van der Werf, P.; García-Burillo, S. +11 more
Aiming to characterise the properties of the molecular gas in the ultra-luminous infrared galaxy Mrk 273 and its outflow, we used the NOEMA interferometer to image the dense-gas molecular tracers HCN, HCO+, HNC, HOC+ and HC3N at ∼86 GHz and ∼256 GHz with angular resolutions of 4ʺ̣9 × 4ʺ̣5 (∼3.7 × 3.4 kpc) and 0ʺ̣61 × …
An Unexpected Detection of Bifurcated Blue Straggler Sequences in the Young Globular Cluster NGC 2173
Deng, Licai; de Grijs, Richard; Li, Chengyuan +2 more
The bifurcated patterns in the color-magnitude diagrams of blue straggler stars (BSSs) have attracted significant attention. This type of special (but rare) pattern of two distinct blue straggler sequences is commonly interpreted as evidence that cluster core-collapse-driven stellar collisions are an efficient formation mechanism. Here, we report …
Mapping Lyman Continuum Escape in Tololo 1247-232
Jaskot, Anne E.; James, Bethan L.; Oey, M. S. +2 more
Low-redshift, spatially resolved Lyman continuum (LyC) emitters allow us to clarify the processes for LyC escape from these starburst galaxies. We use Hubble Space Telescope (HST) WFC3 and ACS imaging of the confirmed low-redshift LyC emitter Tol 1247-232 to study the ionization structure of the gas and its relation to the ionizing star clusters. …
Joint NuSTAR and Chandra analysis of the obscured quasar in IC 2497 - Hanny's Voorwerp system
Schawinski, Kevin; Sartori, Lia F.; Gandhi, Poshak +9 more
We present new Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the core of IC 2497, the galaxy associated with Hanny's Voorwerp. The combined fits of the Chandra (0.5-8 keV) and NuSTAR (3-24 keV) X-ray spectra, together with WISE mid-IR photometry, optical longslit spectroscopy and optical narrow-band imaging, suggest that the galax…
The Young Massive Star Cluster Westerlund 2 Observed with MUSE. I. First Results on the Cluster Internal Motion from Stellar Radial Velocities
Grebel, Eva K.; Kamann, Sebastian; McLeod, Anna Faye +7 more
Westerlund 2 (Wd2) is the central ionizing star cluster of the H II region RCW 49 and the second most massive young star cluster ({\text{}}M=(3.6+/- 0.3)× {10}4 {\text{}}{M}⊙ ) in the Milky Way. Its young age (∼2 Myr) and close proximity to the Sun (∼4 kpc) makes it a perfect target to study stars emerging from their parental…
The September 2017 SEP Event in Context With the Current Solar Cycle: Mars Express ASPERA-3/IMA and MAVEN/SEP Observations
Holmström, Mats; Futaana, Yoshifumi; Ramstad, Robin +5 more
We use Mars Atmosphere and Volatile Evolution/Solar Energetic Particle (MAVEN/SEP) data to estimate the ranges of particle energies that generate background noise in the Analyzer of Space Plasmas and Energetic Atoms-3/Ion Mass Analyzer (IMA) instrument on Mars Express. The particles that generate IMA background counts are estimated to be electrons…
Herschel PACS Observations of 4-10 Myr Old Classical T Tauri Stars in Orion OB1
Qi, Chunhua; Calvet, Nuria; Espaillat, Catherine C. +12 more
We present Herschel PACS observations of eight classical T Tauri Stars in the ∼7-10 Myr old OB1a and the ∼4-5 Myr old OB1b Orion subassociations. Detailed modeling of the broadband spectral energy distributions, particularly the strong silicate emission at 10 µm, shows that these objects are (pre-)transitional disks with some amount of small…