Search Publications
The UV spectral slope β and stellar population of most active star-forming galaxies at z ∼ 4
Yamada, Toru; Yamanaka, Satoshi
We investigate a stellar population of star-forming galaxies at z ∼ 4 by focusing on the slope of their rest-frame ultraviolet (UV) continuum, β, where fλ ∝ λβ. We investigate a sample of bright Lyman break galaxies (LBGs) with i' ≤ 26.0 in the Subaru/XMM-Newton Deep Survey field by using a spectral energy distribution fittin…
Galaxies of the z ∼ 2 Universe. I. Grism-selected Rest-frame Optical Emission-line Galaxies
Yang, Guang; Schneider, Donald P.; Gronwall, Caryl +6 more
Euclid, the Wide Field Infrared Survey Telescope, and the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) will make emission-line selected galaxies the largest observed constituent in the z > 1 universe. However, we only have a limited understanding of the physical properties of galaxies selected via their Lyα or rest-frame optical emiss…
Angular Sizes, Radii, and Effective Temperatures of B-type Stars from Optical Interferometry with the CHARA Array
Gies, Douglas R.; Schaefer, Gail H.; Huber, Daniel +2 more
We present interferometric observations of 25 spectral type-B stars that were made with the Precision Astronomical Visible Observations and the CLassic Interferometry with Multiple Baselines beam combiners at the Center for High Angular Resolution Astronomy Array (CHARA). The observations provide the angular sizes of these stars with an average er…
Super Metal-rich Stars in the LAMOST Survey: A Test on Radial Migration
Tian, H.; Zhao, G.; Chen, Y. Q. +5 more
Super metal-rich stars with [Fe/H] > 0.4 are selected from LAMOST DR6, and two groups, the blue and the red, are found in the T eff versus logg diagram with a temperature gap between them. In combination with Gaia DR2, stellar positions, velocities, and orbits are calculated, and spatial distributions, kinematical properties, and orb…
Kinematic signatures of cluster formation from cool collapse in the Lagoon Nebula cluster NGC 6530
Parker, Richard J.; Wright, Nicholas J.
We examine the mass dependence of the velocity dispersion of stars in the young cluster NGC 6530 to better understand how it formed. Using a large sample of members we find that the proper motion velocity dispersion increases with stellar mass. While this trend is the opposite of that predicted if the cluster were developing energy equipartition, …
Hidden IR structures in NGC 40: signpost of an ancient born-again event
Guerrero, M. A.; Toalá, J. A.; Todt, H. +1 more
We present the analysis of infrared (IR) observations of the planetary nebula NGC 40 together with spectral analysis of its [WC]-type central star HD 826. Spitzer IRS observations were used to produce spectral maps centred at polycyclic aromatic hydrocarbons (PAH) bands and ionic transitions to compare their spatial distribution. The ionic lines s…
Line Profiles of the Calcium I Resonance Line in Cool Metal-polluted White Dwarfs
Dufour, P.; Allard, N. F.; Blouin, S. +2 more
Metal-polluted white dwarfs (DZ stars) are characterized by a helium-rich atmosphere contaminated by heavy elements traces originating from accreted rocky planetesimals. As a detailed spectroscopic analysis of those objects can reveal the composition of the accreted debris, there is a great interest in developing accurate DZ atmosphere models. How…
Bok globule CB 17: polarization, extinction and distance
Medhi, B. J.; Das, H. S.; Choudhury, G. B. +1 more
In this article, the results obtained from a polarimetric study of Bok globule CB 17 in both optical and submillimetre wavelengths are presented. Optical polarimetric observations in the R band (λ = 630 nm, Δλ = 120 nm) were conducted with the 1.04-m Sampurnanand Telescope, Aryabhatta Research Institute of observational sciencES (ARIES), in Nainit…
Moving Groups as the Origin of the Vertical Phase Space Spiral in the Solar Neighborhood
Pérez-Villegas, Angeles; Barros, Douglas A.; Michtchenko, Tatiana A. +1 more
Using Gaia data release 2 (DR2), we analyzed the distribution of stars in the close vicinity of the Sun in the full 3D position-velocity space. We have found no evidence of incomplete phase mixing in the vertical direction of the disk, which could have originated from external events. We show that the vertical phase-space spiral Z-V z …
Merging cold front and AGN feedback in the peculiar galaxy cluster Abell 2626
Pawar, P. K.; Sonkamble, S. S.; Patil, M. K. +1 more
This paper presents the analysis of combined 134 ks Chandra data of a peculiar galaxy cluster Abell 2626. This study confirms the earlier detection of the east cavity at ∼13 kpc and reports the detection of a new cavity at ∼39 kpc to the west of the X-ray peak. The average mechanical power injected by the active galactic nucleus outburst P_cav ∼ 6…