arXiv subjects

Blair C. Conn

Publications and source records attributed to Blair C. Conn.

23 records · Page 2Linked to original sources

arXiv2011

A New Collisional Ring Galaxy at z = 0.111: Auriga's Wheel

We report the serendipitous discovery of a collision ring galaxy, identified as 2MASX J06470249+4554022, which we have dubbed 'Auriga's Wheel', found in a SUPRIME-CAM frame as part of a larger Milky Way survey. This peculiar class of galaxies is the result of a near head-on collision between typically, a late type and an early type galaxy. Subsequent GMOS-N long-slit spectroscopy has confirmed both the relative proximity of the components of this interacting pair and shown it to have a redshift of 0.111. Analysis of the spectroscopy reveals that the late type galaxy is a LINER class Active Galactic Nuclei while the early type galaxy is also potentially an AGN candidate, this is very uncommon amongst known collision ring galaxies. Preliminary modeling of the ring finds an expansion velocity of ~200 kms^-1 consistent with our observations, making the collision about 50 Myr old. The ring currently has a radius of about 10 kpc and a bridge of stars and gas is also visible connecting the two galaxies.

astro-ph.CO↗

arXiv2008

The AAT/WFI survey of the Monoceros Ring and Canis Major Dwarf galaxy: II. from l = (280 - 025)deg

This paper concludes a systematic search for evidence of the Monoceros Ring and Canis Major dwarf galaxy around the Galactic Plane. Presented here are the results for the Galactic longitude range of l = (280 - 025)deg. Testing the claim that the Monoceros Ring encircles the entire Galaxy, this survey attempts to document the position of the Monoceros Ring with increasing Galactic longitude. Additionally, with the discovery of the purported Canis Major dwarf galaxy, searching for more evidence of its interaction is imperative to tracing its path through the Galaxy and understanding its role in the evolution of the Milky Way. Two new detections of the Monoceros Ring have been found at (l, b) = (280,+15)deg and (300,+10)deg. Interestingly, in general there seem to be more detections above the Plane than below it; in this survey around 2/3 of the firm Monoceros Ring detections are in the North. This coincides with the Northern detections appearing to be qualitatively denser and broader than their Southern counterparts. The maximum of the Galactic Warp in the South is also probed in this survey. It is found that these fields do not resemble those in the Canis Major region suggesting that the Warp does not change the shape of the CMD as is witnessed around Canis Major. The origins and morphology of the Monoceros Ring is still elusive primarily due to its enormous extent on the sky. Continued probing of the Galactic Outer Disc is needed before a consensus can be reached on its nature.

astro-ph↗

arXiv2007

The AAT/WFI survey of the Monoceros Ring and Canis Major Dwarf galaxy: I. from l = (193 - 276)o

We present the results of an AAT wide-field camera survey of the stars in the Monoceros Ring and purported Canis Major overdensity in the Galactic longitudes of {\it l} = (193 - 276)$^\circ$. Current numerical simulations suggest that both of these structures are the result of a single on-going accretion event, although an alternative solution is that the warped and flared disc of the Galaxy can explain the origin of both of these structures. Our results show that, with regards the Monoceros Ring, the warped and flared disc is unable to reproduce the locations and strengths of the detections observed around the Galaxy. This supports a non-Galactic origin for this structure. We report 8 new detections and 2 tentative detections of the Monoceros Ring in this survey. The exact nature of the Canis Major overdensity is still unresolved although this survey provides evidence that invoking the Galactic warp is not a sufficient solution when compared with observation. Several fields in this survey are highly inconsistent with the current Galactic disc models that include a warp and flare, to such an extent that explaining their origins with these structures is problematic. (Abridged)

astro-ph↗

arXiv2005

A radial velocity survey of low Galactic latitude structures: II. The Monoceros Ring behind the Canis Major dwarf galaxy

An AAT/2dF Spectrograph Survey of low Galactic latitudes targeting the putative Canis Major dwarf galaxy, and the (possibly) associated tidal debris of stars known as the Monoceros Ring, covering Galactic coordinates 231.5$^{\circ}< ${\it l} $<$ 247.5$^{\circ}$ and -11.8$^{\circ}<${\it b}$<-3.8^{\circ}$, has revealed the presence of the Monoceros Ring in the background of the Canis Major dwarf galaxy. This detection resides at a galactocentric distance of $\sim18.9\pm$0.3\kpc (13.5$\pm$0.3\kpc heliocentric), exhibiting a velocity of $\sim132.8\pm$1.3 $\kms$ with a dispersion of $\sim22.7\pm1.7\kms$; both of these comparable with previous measurements of the Monoceros Ring in nearby fields. This detection highlights the increasing complexity of structure being revealed in recent surveys of the Milky Way thick disk and Halo.

astro-ph↗

arXiv2005

The INT/WFC survey of the Monoceros Ring: Accretion origin or Galactic Anomaly?

We present the results of a wide-field camera survey of the stars in the Monoceros Ring, thought to be an additional structure in the Milky Way of unknown origin. Lying roughly in the plane of the Milky Way, this may represent a unique equatorial accretion event which is contributing to the Thick Disk of the Galaxy. Alternatively, the Monoceros Ring may be a natural part of the Disk formation process. With ten pointings in symmetric pairs above and below the plane of the Galaxy, this survey spans 90 degrees about the Milky Way's equator. Signatures of the stream of stars were detected in three fields, ({\it l},{\it b}) = (118,+16)$^\circ$ and (150,+15)$^\circ$ plus a more tentative detection at (150,-15)$^\circ$. Galactocentric distance estimates to these structures gave $\sim$17, $\sim$17, and $\sim$13 kpc respectively. The Monoceros Ring seems to be present on both sides of the Galactic plane, in a form different to that of the Galactic suggestive of a tidal origin with streams multiply wrapping the Galaxy. A new model of the stream has shown a strong coincidence with our results and has also provided the opportunity to make several more detections in fields in which the stream is less significant. The confirmed detection at ({\it l},{\it b}) = (123,-19)$^\circ$ at $\sim$14, kpc from the Galactic centre allows a re-examination revealing a tentative new detection with a Galactocentric distance of $\sim$21 kpc. (Abridged)

astro-ph↗