Search Publications
The Globular Cluster Populations of Giant Galaxies: Mosaic Imaging of Five Moderate-luminosity Early-type Galaxies
Rhode, Katherine L.; Hargis, Jonathan R.
This paper presents results from wide-field imaging of the globular cluster (GC) systems of five intermediate-luminosity (MV ~ -21 to -22) early-type galaxies. The aim is to accurately quantify the global properties of the GC systems by measuring them out to large radii. We obtained BVR imaging of four lenticular galaxies (NGC 5866, NGC…
Searching for evidence of hydrothermal activity at Apollinaris Mons, Mars
Markiewicz, Wojciech J.; Heggy, Essam; Marzo, Giuseppe A. +5 more
A multidisciplinary approach involving various remote sensing instruments is used to investigate Apollinaris Mons, a prominent volcano on Mars, as well as the surrounding plains for signs of prolonged hydrologic and volcanic, and possibly hydrothermal activity. The main findings include (1) evidence from laser altimetry indicating the large thickn…
Cluster 77 in NGC 4449: The Nucleus of a Satellite Galaxy Being Transformed into a Globular Cluster?
Tosi, M.; van der Marel, R. P.; Aloisi, A. +2 more
We report the discovery in our Hubble Space Telescope Advanced Camera for Surveys B, V, and I images of NGC 4449 of a globular cluster (GC) which appears associated with two tails of blue stars. The cluster is massive (M ~ 1.7 × 106 M ⊙) and highly flattened (epsilon ~ 0.24). From the color-magnitude diagrams of the resolved …
Edge detection applied to Cassini images reveals no measurable displacement of Ontario Lacus' margin between 2005 and 2010
Sotin, Christophe; Barnes, Jason W.; Le Mouélic, Stéphane +8 more
Ontario Lacus is thus far the largest flat-floored topographic depression of Titan's southern hemisphere interpreted as a permanent or ephemeral lake. From 2005 to 2010, it was imaged several times and at various wavelengths by ISS, VIMS and RADAR instruments onboard Cassini's spacecraft. We analyze the position and uncertainty of Ontario Lacus' m…
Doppler shift of hot coronal lines in a moss area of an active region
Solanki, S. K.; Teriaca, L.; Wiegelmann, T. +2 more
The moss is the area at the footpoint of the hot (3 to 5 MK) loops forming the core of the active region where emission is believed to result from the heat flux conducted down to the transition region from the hot loops. Studying the variation of Doppler shift as a function of line formation temperatures over the moss area can give clues on the he…
Bubbles and Knots in the Kinematical Structure of the Bipolar Planetary Nebula NGC 2818
Vázquez, Roberto
High-resolution Hubble Space Telescope archive imaging and high-dispersion spectroscopy are used to study the complex morphological and kinematical structure of the planetary nebula, NGC 2818. We analyze narrowband Hα, [O III], [N II], [S II], and He II images, addressing important morphological features. Ground-based long-slit echelle spectra wer…
On the Polarimetric Signature of Emerging Magnetic Loops in the Quiet Sun
Viticchié, B.
The abundance of Stokes V profiles dominated by one lobe at the locations of emergence of Ω-shaped magnetic loops is evaluated. The emergence events were found in Hinode Solar Optical Telescope/spectro-polarimeter time sequences of quiet-Sun regions. Such a study has the aim of confirming a prediction based on the basic geometrical and physical pr…
Revisiting Algorithms for Generating Surrogate Time Series
Papadakis, I. E.; Brinkmann, W.; Gliozzi, M. +1 more
The method of surrogates is one of the key concepts of nonlinear data analysis. Here, we demonstrate that commonly used algorithms for generating surrogates often fail to generate truly linear time series. Rather, they create surrogate realizations with Fourier phase correlations leading to nondetections of nonlinearities. We argue that reliable s…
Optical identification of six hard X-ray sources from the INTEGRAL and SWIFT all-sky surveys
Bikmaev, I. F.; Lutovinov, A. A.; Revnivtsev, M. G. +1 more
We present results of optical identifications of six hard X-ray sources from the INTEGRAL and Swift all-sky surveys (IGR J03249+4041, SWIFT J1449.5+8602, SWIFT J1542.0-1410, IGR J17009+3559, IGR J18151-1052, IGR J18538-0102). Our optical observations were performed in 2009-2011 with the 6-m BTA telescope (Special Astrophysical Observatory, Nizhnii…
Searching for γ-Ray Blazar Candidates among the Unidentified INTEGRAL Sources
Tosti, G.; Massaro, F.; Paggi, A. +1 more
The identification of low-energy counterparts for γ-ray sources is one of the biggest challenges in modern γ-ray astronomy. Recently, we developed and successfully applied a new association method to recognize γ-ray blazar candidates that could be possible counterparts for the unidentified γ-ray sources above 100 MeV in the second Fermi Large Area…