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Fragmentation of star-forming filaments in the X-shaped nebula of the California molecular cloud
André, Ph.; Men'shchikov, A.; Wang, Ke +1 more
Context. Dense molecular filaments are central to the star formation process, but the detailed manner in which they fragment into prestellar cores is not well understood yet.
Aims: Here, we investigate the fragmentation properties and dynamical state of several star-forming filaments in the X-shaped nebula region of the California molecular c…
The Open Universe VOU-Blazars tool
Giommi, P.; Chang, Y. -L.; Brandt, C. H.
Blazars are a remarkable type of Active Galactic Nuclei (AGN) that are playing an important and rapidly growing role in today's multi-frequency and multi-messenger astrophysics. In the past several years, blazars have been discovered in relatively large numbers in radio, microwave, X-ray and gamma-ray surveys, and more recently have been associate…
Inverse stellar population age gradients of post-starburst galaxies at z = 0.8 with LEGA-C
Bell, Eric F.; D'Eugenio, Francesco; Franx, Marijn +13 more
We use deep, spatially resolved spectroscopy from the Large Early Galaxy Astrophysics Census Survey to study radial variations in the stellar population of 17 spectroscopically selected post-starburst (PSB) galaxies. We use spectral fitting to measure two Lick indices, H δA and Fe 4383 , and find that, on average, PSB galaxies have radi…
WIYN Open Cluster Study. LXXXII. Radial-velocity Measurements and Spectroscopic Binary Orbits in the Open Cluster NGC 7789
Platais, Imants; Tofflemire, Benjamin M.; Mathieu, Robert D. +4 more
We present an extensive time-series radial-velocity (RV) survey of stars in the rich open cluster NGC 7789 (1.6 Gyr, [Fe/H] = +0.02). The stellar sample lies within an 18' circular radius from the cluster center (10 pc in projection, or about 2 core radii), and includes giants, red clump stars, blue stragglers, red stragglers, sub-subgiants, and m…
Discovery of new stellar groups in the Orion complex. Towards a robust unsupervised approach
Alves, João; Adamo, Angela; D'Onghia, Elena +1 more
We test the ability of two unsupervised machine learning algorithms, EnLink and Shared Nearest Neighbor (SNN), to identify stellar groupings in the Orion star-forming complex as an application to the 5D astrometric data from Gaia DR2. The algorithms represent two distinct approaches to limiting user bias when selecting parameter values and evaluat…
Spitzer + VLTI-GRAVITY Measure the Lens Mass of a Nearby Microlensing Event
Feliz, Dax L.; Zang, Weicheng; Gould, Andrew +26 more
We report the lens mass and distance measurements of the nearby microlensing event TCP J05074264+2447555 (Kojima-1). We measure the microlens parallax vector ${{\boldsymbol{\pi }}}_{{\rm{E}}}$ using Spitzer and ground-based light curves with constraints on the direction of lens-source relative proper motion derived from Very Large Telescope Interf…
Hunting for Runaways from the Orion Nebula Cluster
Tan, Jonathan C.; Eyer, Laurent; Farias, Juan P.
We use Gaia DR2 to hunt for runaway stars from the Orion Nebula Cluster (ONC). We search a region extending 45° around the ONC and out to 1 kpc to find sources that have overlapped in angular position with the cluster in the last ∼10 Myr. We find ∼17,000 runaway/walkaway candidates that satisfy this 2D traceback condition. Most of these are expect…
The Fornax 3D project: Globular clusters tracing kinematics and metallicities
Viaene, S.; Hilker, M.; Pinna, F. +15 more
Globular clusters (GCs) are found ubiquitously in massive galaxies and due to their old ages, they are regarded as fossil records of galaxy evolution. Spectroscopic studies of GC systems are often limited to the outskirts of galaxies, where GCs stand out against the galaxy background and serve as bright tracers of galaxy assembly. In this work, we…
The Gaia-ESO Survey: detection and characterisation of single-line spectroscopic binaries
Gilmore, G.; Bayo, A.; Mowlavi, N. +26 more
Context. Multiple stellar systems play a fundamental role in the formation and evolution of stellar populations in galaxies. Recent and ongoing large ground-based multi-object spectroscopic surveys significantly increase the sample of spectroscopic binaries (SBs) allowing analyses of their statistical properties.
Aims: We investigate the repe…
Unsupervised machine learning for transient discovery in deeper, wider, faster light curves
Andreoni, Igor; Mahabal, Ashish; Cooke, Jeff +7 more
Identification of anomalous light curves within time-domain surveys is often challenging. In addition, with the growing number of wide-field surveys and the volume of data produced exceeding astronomers' ability for manual evaluation, outlier and anomaly detection is becoming vital for transient science. We present an unsupervised method for trans…