Related papers: Interacting system NGC 7805/6 (Arp 112) and its ti…

With a spectral type of T10, UGPS J072227.51-054031.2 is one of the coolest objects known to date in the solar neighborhood. Multiple systems are relatively common among early and mid-T dwarfs. We search for faint and close companions…

The hydrogen envelope is the outermost layer of a DA white dwarf; it makes up the entirety of the stellar photosphere, and yet its typical extent is difficult to model theoretically and remains poorly observationally constrained. As a…

We present the analysis of a survey of atomic and molecular gas in interacting and merging galaxies (Horellou & Booth 1997). The sample is optically selected and contains all interacting galaxies (~ 60 systems) in a well-defined region of…

We present a study of a previously identified candidate jellyfish galaxy in the Abell 2744 cluster, F0083, which showed faint signs of a tidal interaction in archival imaging. We used publicly available PSF-matched deep photometric data…

We present optical (UBVJ), ultraviolet (FUV, NUV), and high resolution atomic hydrogen (HI) observations of the nearby blue compact dwarf (BCD), VII Zw 403. We find that VII Zw 403 has a relatively high HI mass-to-light ratio for a BCD. The…

We report on the results from deep HI observations, performed with the Karoo Array Telescope and with the Karl G. Jansky Very Large Array of the loose galaxy group centred on the early-type galaxy IC 1459. The main result from our…

On 2011 August 11, INTEGRAL discovered the hard X-ray source IGR J17361-4441 near the centre of the globular cluster NGC 6388. Follow up observations with Chandra showed the position of the transient was inconsistent with the cluster…

In this paper we describe results from the Arecibo Galaxy Environments Survey (AGES). The survey reaches column densities of ~3x10^18 cm^-2 and masses of ~10^7 M_O, over individual regions of order 10 sq deg in size, out to a maximum…

We present Australia Telescope Compact Array (ATCA) HI imaging of the edge-on galaxy NGC 1596, which was recently found to have counter-rotating ionized gas in its center (<15"). We find a large HI envelope associated with a nearby…

We have derived nebular abundances for 10 dwarf galaxies belonging to the M81 Group, including several galaxies which do not have abundances previously reported in the literature. For each galaxy, multiple H \ii regions were observed with…

NGC 4490/85 (UGC 7651/48) or Arp 269 is well known for being one of the closest interacting/merging galactic systems. NGC 4490 has a high star formation rate (SFR) and is surrounded by an enormous HI feature stretching about 60 kpc north…

Galaxy harassment has been proposed as a physical process that morphologically transforms low surface density disc galaxies into dwarf elliptical galaxies in clusters. It has been used to link the observed very different morphology of…

Hubble Space Telescope images of the galaxies NGC 2207 and IC 2163 show star formation and dust structures in a system that has experienced a recent grazing encounter. Tidal forces from NGC 2207 compressed and elongated the disk of IC 2163,…

We present a comparison of semi-analytic models of the phase-space structure of tidal debris with observations of stars associated with the Sagittarius dwarf galaxy (Sgr). We find that many features in the data can be explained by these…

I present observations of the Hickson Compact Group 88 (HCG88) obtained during the commissioning of a new 28-inch telescope at the Wise Observatory. This galaxy group was advertised to be non-interacting, or to be in a very early…

We present initial results from a deep neutral hydrogen (HI) survey of the HALOGAS galaxy sample, which includes the spiral galaxies NGC891, NGC925, NGC4414, and NGC4565, performed with the Robert C. Byrd Green Bank Telescope (GBT). The…

We derive quantitative star formation histories of the four suspected tidal dwarf galaxies in the M81 group, HolmbergIX, BK3N, Arp-loop (A0952+69), and Garland, using Hubble Space Telescope/Wide Field Planetary Camera2 images in F606W and…

The spectacular head-on collision of the two gas-rich galaxies of the Taffy system, UGC 12914/15, gives us a unique opportunity to study the consequences of a direct ISM-ISM collision. To interpret existing multi-wavelength observations, we…

We have carried out a search for late-type T dwarfs in the UKIDSS Galactic Plane Survey 6th Data Release. The search yielded two persuasive candidates, both of which have been confirmed as T dwarfs. The brightest, UGPS J0521+3640 has been…

We report the discovery and multiwavelength followup of LEDA 1313424 ("Bullseye"), a collisional ring galaxy (CRG) with nine readily-identified rings -- the most so far reported for a CRG. These data shed new light on the rapid, multi-ring…