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Post Info TOPIC: NGC 300


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Posts: 131433
Date:
KSP-OT-201509a
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Title: Discovery of a rapid, luminous nova in NGC 300 by the KMTNet Supernova Program
Author: John Antoniadis, Dae-Sik Moon, Yuan Qi Ni, Dong-Jin Kim, Yongseok Lee, Hilding Neilson

We present the discovery of a rapidly evolving transient by the Korean Microlensing Telescope Network Supernova Program (KSP). KSP is a novel high-cadence supernova survey that offers deep (~21.5 mag in BVI bands) nearly continuous wide-field monitoring for the discovery of early and/or fast optical transients. KSP-OT-201509a, reported here, was discovered on 2015 September 27 during the KSP commissioning run in the direction of the nearby galaxy NGC~300, and stayed above detection limit for ~ 22 days. We use our BVI light-curves to constrain the ascent rate, -3.7(7) mag day^- in V, decay time scale, t^{V}_{2}=1.7(6) days, and peak absolute magnitude, -9.65 \leq MV \leq -9.25 mag. We also find evidence for a short-lived pre-maximum halt in all bands. The peak luminosity and lightcurve evolution make KSP-OT-201509a consistent with a bright, rapidly decaying nova outburst. We discuss constraints on the nature of the progenitor and its environment using archival HST/ACS images and conclude with a broad discussion on the nature of the system.

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Posts: 131433
Date:
Caldwell 70
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NGC 300 (also Caldwell 70, ESO 295-20, IRAS 00528-3758, MCG -6-3-5 and PGC 3238) is a magnitude +9.0 near face-on spiral galaxy located 6.07 ▒0.23 million light-years away in the constellation Sculptor.

The galaxy was discovered by Scottish astronomer James Dunlop using a homemade 9-foot, 22.86 cm (9 inch) f/12 speculum Newtonian reflector at Paramatta, New South Wales, Australia, on the 5th August 1826.

Right Ascension 00h 54m 53.3s, Declination -37░ 41' 04"

áIt is one of the closest galaxies to the Local Group, and probably lies between us and the Sculptor Group. It is the brightest of the five main spirals in the direction of the Sculptor Group. It is inclined at an angle of 42░ when viewed from earth and shares many characteristics of the Triangulum Galaxy
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Posts: 131433
Date:
RE: NGC 300
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Title: A catalogue of planetary nebula candidates in the Sculptor spiral galaxy NGC 300
Authors: Miriam Pena, Jonnathan Reyes-Perez, Liliana Hernandez-Martinez, Miguel Perez-Guillen

[OIII]5007 on-band off-band images, obtained with the VLT and FORS2 spectrograph in two zones (center and outskirts) of the spiral galaxy NGC300, are analysed searching for emission line objects. In particular we search for planetary nebula (PN) candidates to analyse their distribution and luminosity properties, to perform follow-up spectroscopy, and to study the planetary nebula luminosity function, PNLF. In the continuum-subtracted images, a large number of emission line objects were detected. From this sample we selected as PN candidates those objects with stellar appearance and no detectable central star. [OIII]5007 instrumental magnitudes were measured and calibrated by using spectrophotometric data from the follow-up spectroscopy. We identified more than a hundred PN candidates and a number of compact HII regions. The PN sample is the largest one reported for this galaxy so far. For all the objects we present coordinates, instrumental [OIII]5007 magnitudes and apparent nebular [OIII]5007 fluxes and magnitudes. The [OIII]5007 observed luminosity function for PNe (PNLF) was calculated for the whole sample and for the central and outskirts samples. The three PNLF are similar within uncertainties. We fit the empirical PNLF to the observed PNLF for all the samples. From our best fit for the whole sample we derived a maximum value for the apparent magnitudes of m*(5007)=22.019▒0.022 and we obtained a tentative estimate of the distance modulus m(5007)-M(5007)= 26.29 {+0.12} {-0.22} mag, which agrees well with the recent value derived from Cepheid stars.

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Title: The Chandra Local Volume Survey: The X-ray Point Source Catalogue of NGC 300
Authors: Breanna Binder, Benjamin F. Williams, Michael Eracleous, Terrance J. Gaetz, Paul P. Plucinsky, Evan D. Skillman, Julianne J. Dalcanton, Scott F. Anderson, Daniel R. Weisz, Albert K. H. Kong

We present the source catalogue of a new Chandra ACIS-I observation of NGC 300 obtained as part of the Chandra Local Volume Survey. Our 63 ks exposure covers ~88% of the D25 isophote (R~6.3 kpc) and yields a catalogue of 95 X-ray point sources detected at high significance to a limiting unabsorbed 0.35-8 keV luminosity of ~10^36 erg s^-1. Sources were cross-correlated with a previous XMM-Newton catalogue, and we find 75 "X-ray transient candidate" sources that were detected by one observatory, but not the other. We derive an X-ray scale length of 1.7▒0.2 kpc and a recent star formation rate of 0.12 solar masses yr^-1, in excellent agreement with optical observations. Deep, multi-colour imaging from the Hubble Space Telescope, covering ~32% of our Chandra field, was used to search for optical counterparts to the X-ray sources, and we have developed a new source classification scheme to determine which sources are likely X-ray binaries, supernova remnants, and background AGN candidates. Finally, we present the X-ray luminosity functions (XLFs) at different X-ray energies, and we find the total NGC 300 X-ray point source population to be consistent with other late-type galaxies hosting young stellar populations (<50 Myr). We find XLF of sources associated with older stellar populations has a steeper slope than the XLF of X-ray sources coinciding with young stellar populations, consistent with theoretical predictions.

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Title: Radio-Continuum study of the Nearby Sculptor Group Galaxies. Part 1: NGC 300 at lambda = 20 cm
Authors: Timothy J. Galvin, Miroslav D. Filipovic, Evan J. Crawford, Graeme Wong, Jeff L. Payne, Ain De Horta, Graeme L. White, Nick Tothill, Danica Draskovic, Thomas G. Pannuti, Caleb K. Grimes, Benjamin J. Cahall, William C. Millar, Seppo Laine

A series of new radio-continuum (lambda=20 cm) mosaic images focused on the NGC 300 galactic system were produced using archived observational data from the VLA and/or ATCA. These new images are both very sensitive (rms=60 microJy) and feature high angular resolution (<10"). The most prominent new feature is the galaxy's extended radio-continuum emission, which does not match its optical appearance. Using these newly created images a number of previously unidentified discrete sources have been discovered. Furthermore, we demonstrate that a joint deconvolution approach to imaging this complete data-set is inferior when compared to an immerge approach.

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