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HD 96446: a long-period binary with a strongly magnetic He-rich primary with β Cephei pulsations
Järvinen, S.; González, J. F.; Butler, K. +14 more
Aims: HD 96446 is a magnetic B2p He-strong star that has been reported to be a β Cep pulsator. We present a detailed spectroscopic analysis of this object based on an intensive observational data set obtained in a multisite campaign with the spectrographs CORALIE, FEROS, and HARPS (La Silla); UVES (Paranal); HERCULES (Mt. John Observatory); a…
Extended star-forming regions within galaxies in a dense proto-cluster core at z = 2.53
Suzuki, Tomoko L.; Minowa, Yosuke; Koyama, Yusei +5 more
At z ∼ 2, star formation activity is thought to be high even in high-density environments such as galaxy clusters and proto-clusters. One of the critical but outstanding issues is if the structural growth of star-forming galaxies can differ depending on their surrounding environments. In order to investigate how galaxies grow their structures and …
Evidence of Hubble Flow-like Motion of Young Stellar Populations away from the Perseus Arm
Hernández, Jesús; Roman-Lopes, Alexandre; Tapia, Mauricio +2 more
In this Letter we present evidence of the coherent outward motion of a sample of young stars (t < 30 Myr) in the Perseus Arm, whose apparent origin is located in the vicinity of the W3/W4/W5 complex. Using astrometric and photometric data from the Gaia Data Release 2 catalog of an 8◦ radius field centered near W4, we selected a sampl…
A Search for Variable Stars in the Globular Cluster M4 with K2
Wallace, Joshua J.; Hartman, Joel D.; Bakos, Gáspár Á. +1 more
We extract light curves for 4554 objects with 9 < G < 19 in the K2 superstamp observations of the globular cluster M4, including 3784 cluster members, and search for variability. Among cluster-member objects, we detect 66 variables, of which 52 are new discoveries. Among objects not belonging to the cluster, we detect 24 variables, of which …
The 3D shape of Type IIb SN 2011hs
Spyromilio, J.; Wang, L.; Wheeler, J. C. +10 more
We observed seven epochs of spectropolarimetry in optical wavelengths for the Type IIb SN 2011hs, ranging from -3 to +40 d with respect to V-band maximum. A high degree of interstellar polarization was detected (up to ∼3 per cent), with a peak lying blueward of 4500 Å. Similar behaviours have been seen in some Type Ia supernovae (SNe), but had nev…
Observations of Asymmetric Lobe Convection for Weak and Strong Tail Activity
Østgaard, N.; Tenfjord, P.; Reistad, J. P. +6 more
In this study we use high-quality convection data from the Electron Drift Instrument on board Cluster to investigate how near-Earth tail activity affects the average convection pattern in the magnetotail lobes when the interplanetary magnetic field has a dominating east-west (By) component. Two different proxies have been used to repres…
Discovery of a giant and luminous Lyα+C IV+He II nebula at z = 3.326 with extreme emission line ratios
Pérez-Fournon, I.; Ivison, R. J.; Omont, A. +17 more
We present the discovery of HLock01-LAB, a luminous and large Lyα nebula at z = 3.326. Medium-band imaging and long-slit spectroscopic observations with the Gran Telescopio Canarias reveal extended emission in the Lyα 1215 Å, C IV 1550 Å, and He II 1640 Å lines over ∼100 kpc, and a total luminosity LLyα = (6.4 ± 0.1)×1044 erg…
The extreme O-type spectroscopic binary HD 93129A. A quantitative, multiwavelength analysis
Gruner, D.; Hamann, W. -R.; Oskinova, L. M. +6 more
Context. HD 93129A was classified as the earliest O-type star in the Galaxy (O2 If*) and is considered as the prototype of its spectral class. However, interferometry shows that this object is a binary system, while recent observations even suggest a triple configuration. None of the previous spectral analyses of this object accounted for its mult…
Multiple Stellar Populations of Globular Clusters from Homogeneous Ca-CN-CH Photometry. V. {{cn}}_{JWL}}^{{\prime} } as a Surrogate cn JWL Index and NGC 6723
Lee, Jae-Woo
We introduce new color indices {{cn}}JWL}{\prime } (=Ca CTIO - Ca JWL) and ch JWL [=(JWL43 - b) - (b - y)], accurate photometric measures of the CN band at λ3883 and the CH G band, respectively, in the study of the multiple populations (MPs) in globular clusters (GCs). Our photometric CN-CH re…
Validation of the IPSL Venus GCM Thermal Structure with Venus Express Data
Piccioni, Giuseppe; Tellmann, Silvia; Lebonnois, Sebastien +4 more
General circulation models (GCMs) are valuable instruments to understand the most peculiar features in the atmospheres of planets and the mechanisms behind their dynamics. Venus makes no exception and it has been extensively studied thanks to GCMs. Here we validate the current version of the Institut Pierre Simon Laplace (IPSL) Venus GCM, by means…