Search Publications
Impact of theoretical priors in cosmological analyses: The case of single field quintessence
Peirone, Simone; Raveri, Marco; Silvestri, Alessandra +1 more
We investigate the impact of general conditions of theoretical stability and cosmological viability on dynamical dark energy models. As a powerful example, we study whether minimally coupled, single field quintessence models that are safe from ghost instabilities, can source the Chevallier-Polarski-Linder (CPL) expansion history recently shown to …
Modeling the Gravitational Potential of a Cosmological Dark Matter Halo with Stellar Streams
Helmi, Amina; Sanderson, Robyn E.; Hartke, Johanna
Stellar streams result from the tidal disruption of satellites and star clusters as they orbit a host galaxy, and can be very sensitive probes of the gravitational potential of the host system. We select and study narrow stellar streams formed in a Milky-Way-like dark matter halo of the Aquarius suite of cosmological simulations, to determine if t…
A Suzaku, NuSTAR, and XMM-Newton view on variable absorption and relativistic reflection in NGC 4151
Dauser, T.; Wilms, J.; Kadler, M. +6 more
We disentangle X-ray disk reflection from complex line-of-sight absorption in the nearby Seyfert NGC 4151, using a suite of Suzaku, NuSTAR, and XMM-Newton observations. Extending upon earlier published work, we pursue a physically motivated model using the latest angle-resolved version of the lamp-post geometry reflection model relxillCp_lp togeth…
Hierarchical star formation across the grand-design spiral NGC 1566
Gouliermis, Dimitrios A.; Grebel, Eva K.; Smith, Linda J. +19 more
We investigate how star formation is spatially organized in the grand-design spiral NGC 1566 from deep Hubble Space Telescope photometry with the Legacy ExtraGalactic UV Survey. Our contour-based clustering analysis reveals 890 distinct stellar conglomerations at various levels of significance. These star-forming complexes are organized in a hiera…
Probing cosmological isotropy with Planck Sunyaev-Zeldovich galaxy clusters
Bernui, A.; Ferreira, I. S.; Alcaniz, J. S. +1 more
We probe the statistical isotropy hypothesis of the large-scale structure with the second Planck Sunyaev-Zeldovich (PSZ2) galaxy clusters data set. Our analysis adopts a statistical-geometrical method that compares the two-point angular-correlation function of objects in antipodal patches of the sky. Given possible observational biases, such as th…
A Multi-wavelength Study of the Turbulent Central Engine of the Low-mass AGN Hosted by NGC 404
Davis, Timothy A.; Nguyen, Dieu D.; Nyland, Kristina +9 more
The nearby dwarf galaxy NGC 404 harbors a low-luminosity active galactic nucleus powered by the lowest-mass (<150,000 M ⊙) central massive black hole (MBH), with a dynamical mass constraint, currently known, thus providing a rare low-redshift analog to the MBH “seeds” that formed in the early universe. Here, we present new imaging of…
A high-resolution H I study towards the supernova remnant Puppis A and its environments
Reynoso, E. M.; Cichowolski, S.; Walsh, A. J.
We observed the supernova remnant Puppis A in the 21 cm line with the Australia Telescope Compact Array with the aim of determining the systemic velocity and, hence, the corresponding kinematic distance. For the compact, background sources in the field, we obtain absorption spectra by applying two methods: (a) subtracting profiles on- and off-sour…
Small Jupiter Trojans Survey with the Subaru/Hyper Suprime-Cam
Terai, Tsuyoshi; Yoshida, Fumi
We observed the L4 Jupiter Trojans (JTs) swarm using the Hyper Suprime-Cam attached to the 8.2 m Subaru Telescope on 2015 March 30 (UT). The survey covered ∼26 deg2 of sky area near the opposition and around the ecliptic plane with a 240 s exposure time in the r-band filter through the entire survey. We detected 631 L4 JTs in the survey…
The detection of variable radio emission from the fast rotating magnetic hot B-star HR\xA07355 and evidence for its X-ray aurorae
Umana, G.; Leone, F.; Ignace, R. +6 more
In this paper, we investigate the multiwavelength properties of the magnetic early B-type star HR 7355. We present its radio light curves at several frequencies, taken with the Jansky Very Large Array, and X-ray spectra, taken with the XMM-Newton X-ray telescope. Modelling of the radio light curves for the Stokes I and V provides a quantitative an…
Photospheric activity of the Sun with VIRGO and GOLF. Comparison with standard activity proxies
García, R. A.; Pallé, P. L.; Bertello, L. +3 more
We study the variability of solar activity using new photospheric proxies originally developed for the analysis of stellar magnetism with the CoRoT and Kepler photometric observations. These proxies were obtained by tracking the temporal modulations in the observations associated with the spots and magnetic features as the Sun rotates. We analyzed…