Search Publications
Toward a Better Understanding of the Distance Scale from RR Lyrae Variable Stars: A Case Study for the Inner Halo Globular Cluster NGC 6723
López-Morales, Mercedes; Lee, Jae-Woo; Kang, Young-Woon +3 more
We present BV photometry for 54 variables in the metal-rich inner halo globular cluster NGC 6723. With the discovery of new RR Lyrae variables (RRLs), we obtain langP abrang = 0.541 ± 0.066 and langP crang = 0.292 ± 0.030 day, n(c)/n(ab+c) = 0.167, and langV(RR)rangint = 15.459 ± 0.055. We carry out the Fourier dec…
Dwarf galaxies in the Perseus Cluster: further evidence for a disc origin for dwarf ellipticals
Penny, Samantha J.; Forbes, Duncan A.; Pimbblet, Kevin A. +1 more
We present the results of a Keck-ESI (Echellette Spectrograph and Imager) spectroscopic study of six dwarf elliptical (dE) galaxies in the Perseus Cluster core, and confirm two dwarfs as cluster members for the first time. All six dEs follow the size-magnitude relation for dE/dSph galaxies. Central velocity dispersions are measured for three Perse…
Probing a dark matter density spike at the Galactic Center
Silk, Joseph; Lacroix, Thomas; BÅ`hm, Céline
The dark matter halo profile in the inner Galaxy is very uncertain. Yet its radial dependence toward the Galactic Center is of crucial importance for the determination of the gamma-ray and radio fluxes originating from dark matter annihilations. Here we use synchrotron emission to probe the dark matter energy distribution in the inner Galaxy. We f…
Measuring growth index in a Universe with sterile neutrinos
Zhang, Jing-Fei; Zhang, Xin; Li, Yun-He
Consistency tests for the general relativity (GR) can be performed by constraining the growth index γ using the measurements of redshift-space distortions (RSD) in conjunction with other observations. In previous studies, deviations from the GR expected value of γ ≈ 0.55 at the 2-3σ level were found. In this work, we reconsider the measurement of …
Preservation of ancient ice at Pavonis and Arsia Mons: Tropical mountain glacier deposits on Mars
Head, James W.; Weiss, David K.
Large tropical mountain glacier (TMG) deposits on the northwest flanks of the Tharsis Montes and Olympus Mons volcanoes are interpreted to be the record of ancient climates characteristic of Mars several hundred million years ago when planetary spin-axis obliquity was ~45°. During this era, polar volatiles (predominantly H2O) were mobil…
High Resolution Radio and Optical Observations of the Central Starburst in the Low-metallicity Dwarf Galaxy II Zw 40
Johnson, Kelsey E.; Reines, Amy E.; Kepley, Amanda A. +1 more
The extent to which star formation varies in galaxies with low masses, low metallicities, and high star formation rate surface densities is not well constrained. To gain insight into star formation under these physical conditions, this paper estimates the ionizing photon fluxes, masses, and ages for young massive clusters in the central region of …
Separate constraints on early and late cosmology
Audren, B.
Since the public release of Planck data, several attempts have been made to explain the observed small tensions with other data sets, most of them involving an extension of the Λ cold dark matter (ΛCDM) model. We try here an alternative approach to the data analysis, based on separating the constraints coming from the different epochs in cosmology…
Variations in the pulsation and spectral characteristics of OAO 1657-415
Maitra, Chandreyee; Paul, Biswajit; Pradhan, Pragati +2 more
We present broad-band pulsation and spectral characteristics of the accreting X-ray pulsar OAO 1657-415 with a 2.2 d long Suzaku observation carried out covering its orbital phase range ∼0.4-0.6, with respect to the mid-eclipse. During the last third of the observation, the X-ray count rate in both the X-ray Imaging Spectrometer (XIS) and the HXD-…
Integrated method for crater detection from topography and optical images and the new PH9224GT catalogue of Phobos impact craters
Lončarić, Sven; Salamunićcar, Goran; Pina, Pedro +2 more
In a large majority of lunar and planetary surface images, impact craters are the most abundant geological features. Therefore, it is not surprising that crater detection algorithms (CDAs) are one of the most studied subjects of image processing and analysis in lunar and planetary science. In this work we are proposing an Integrated CDA, consistin…
Galactic winds and stellar populations in Lyman α emitting galaxies at z ∼ 3.1
Finkelstein, S. L.; Malhotra, S.; Rhoads, J. E. +4 more
We present a sample of 33 spectroscopically confirmed z ∼ 3.1 Lyα-emitting galaxies (LAEs) in the Cosmological Evolution Survey (COSMOS) field. This paper details the narrow-band survey we conducted to detect the LAE sample, the optical spectroscopy we performed to confirm the nature of these LAEs, and a new near-infrared spectroscopic detection o…