A Low HI Column Density Filament in NGC 2403
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The HERACLES View of the H -To-HI Ratio in Galaxies
The HERACLES View of the H2-to-HI Ratio in Galaxies Adam Leroy (NRAO, Hubble Fellow) Fabian Walter, Frank Bigiel, the HERACLES and THINGS teams The Saturday Morning Summary • Star formation rate vs. gas relation on ~kpc scales breaks apart into: A relatively universal CO-SFR relation in nearby disks Systematic environmental scalings in the CO-to-HI ratio • The CO-to-HI ratio is a strong function of radius, total gas, and stellar surface density correlated with ISM properties: dust-to-gas ratio, pressure harder to link to dynamics: gravitational instability, arms • Interpretation: the CO-to-HI ratio traces the efficiency of GMC formation Density and dust can explain much of the observed behavior heracles Fabian Walter Erik Rosolowsky MPIA UBC Frank Bigiel Eva Schinnerer UC Berkeley THINGS plus… MPIA Elias Brinks Antonio Usero Gaelle Dumas U Hertfordshire OAN, Madrid MPIA Erwin de Blok Andreas Schruba Helmut Wiesemeyer U Cape Town IRAM … MPIA Rob Kennicutt Axel Weiss Karl Schuster Cambridge MPIfR IRAM Barry Madore Carsten Kramer Karin Sandstrom Carnegie IRAM MPIA Michele Thornley Daniela Calzetti Kelly Foyle Bucknell UMass MPIA Collaborators The HERA CO-Line Extragalactic Survey First maps Leroy et al. (2009) • IRAM 30m Large Program to map CO J = 2→1 line • Instrument: HERA receiver array operating at 230 GHz • 47 galaxies: dwarfs to starbursts and massive spirals -2 • Very wide-field (~ r25) and sensitive (σ ~ 1-2 Msun pc ) NGS The HI Nearby Galaxy Survey HI Walter et al. (2008), AJ Special Issue (2008) • VLA HI maps of 34 galaxies: -
Big Halpha Kinematical Sample of Barred Spiral Galaxies - I
BhaBAR: Big Halpha kinematical sample of BARred spiral galaxies - I. Fabry-Perot Observations of 21 galaxies O. Hernandez, C. Carignan, P. Amram, L. Chemin, O. Daigle To cite this version: O. Hernandez, C. Carignan, P. Amram, L. Chemin, O. Daigle. BhaBAR: Big Halpha kinematical sample of BARred spiral galaxies - I. Fabry-Perot Observations of 21 galaxies. Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2005, 360 Issue 4, pp.1201. 10.1111/j.1365-2966.2005.09125.x. hal-00014446 HAL Id: hal-00014446 https://hal.archives-ouvertes.fr/hal-00014446 Submitted on 26 Jan 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Mon. Not. R. Astron. Soc. 360, 1201–1230 (2005) doi:10.1111/j.1365-2966.2005.09125.x BHαBAR: big Hα kinematical sample of barred spiral galaxies – I. Fabry–Perot observations of 21 galaxies O. Hernandez,1,2 † C. Carignan,1 P. Amram,2 L. Chemin1 and O. Daigle1 1Observatoire du mont Megantic,´ LAE, Universitede´ Montreal,´ CP 6128 succ. centre ville, Montreal,´ Quebec,´ Canada H3C 3J7 2Observatoire Astronomique de Marseille Provence et LAM, 2 pl. -
Luminous Blue Variables
Review Luminous Blue Variables Kerstin Weis 1* and Dominik J. Bomans 1,2,3 1 Astronomical Institute, Faculty for Physics and Astronomy, Ruhr University Bochum, 44801 Bochum, Germany 2 Department Plasmas with Complex Interactions, Ruhr University Bochum, 44801 Bochum, Germany 3 Ruhr Astroparticle and Plasma Physics (RAPP) Center, 44801 Bochum, Germany Received: 29 October 2019; Accepted: 18 February 2020; Published: 29 February 2020 Abstract: Luminous Blue Variables are massive evolved stars, here we introduce this outstanding class of objects. Described are the specific characteristics, the evolutionary state and what they are connected to other phases and types of massive stars. Our current knowledge of LBVs is limited by the fact that in comparison to other stellar classes and phases only a few “true” LBVs are known. This results from the lack of a unique, fast and always reliable identification scheme for LBVs. It literally takes time to get a true classification of a LBV. In addition the short duration of the LBV phase makes it even harder to catch and identify a star as LBV. We summarize here what is known so far, give an overview of the LBV population and the list of LBV host galaxies. LBV are clearly an important and still not fully understood phase in the live of (very) massive stars, especially due to the large and time variable mass loss during the LBV phase. We like to emphasize again the problem how to clearly identify LBV and that there are more than just one type of LBVs: The giant eruption LBVs or h Car analogs and the S Dor cycle LBVs. -
How to Make $1000 with Your Telescope! – 4 Stargazers' Diary
Fort Worth Astronomical Society (Est. 1949) February 2010 : Astronomical League Member Club Calendar – 2 Opportunities & The Sky this Month – 3 How to Make $1000 with your Telescope! – 4 Astronaut Sally Ride to speak at UTA – 4 Aurgia the Charioteer – 5 Stargazers’ Diary – 6 Bode’s Galaxy by Steve Tuttle 1 February 2010 Sunday Monday Tuesday Wednesday Thursday Friday Saturday 1 2 3 4 5 6 Algol at Minima Last Qtr Moon Æ 5:48 am 11:07 pm Top ten binocular deep-sky objects for February: M35, M41, M46, M47, M50, M93, NGC 2244, NGC 2264, NGC 2301, NGC 2360 Top ten deep-sky objects for February: M35, M41, M46, M47, M50, M93, NGC 2261, NGC 2362, NGC 2392, NGC 2403 7 8 9 10 11 12 13 Algol at Minima Morning sports a Moon at Apogee New Moon Æ super thin crescent (252,612 miles) 8:51 am 7:56 pm Moon 8:00 pm 3RF Star Party Make use of the New Moon Weekend for . better viewing at the Dark Sky Site See Notes Below New Moon New Moon Weekend Weekend 14 15 16 17 18 19 20 Presidents Day 3RF Star Party Valentine’s Day FWAS Traveler’s Guide Meeting to the Planets UTA’s Maverick Clyde Tombaugh Ranger 8 returns Normal Room premiers on Speakers Series discovered Pluto photographs and NatGeo 7pm Sally Ride “Fat Tuesday” Ash Wednesday 80 years ago. impacts Moon. 21 22 23 24 25 26 27 Algol at Minima First Qtr Moon Moon at Perigee Å (222,345 miles) 6:42 pm 12:52 am 4 pm {Low in the NW) Algol at Minima Æ 9:43 pm Challenge binary star for month: 15 Lyncis (Lynx) Challenge deep-sky object for month: IC 443 (Gemini) Notable carbon star for month: BL Orionis (Orion) 28 Notes: Full Moon Look for a very thin waning crescent moon perched just above and slightly right of tiny Mercury on the morning of 10:38 pm Feb. -
Can Stellar Winds Account for Temperature Fluctuations in H II
A&A 379, 1017–1023 (2001) Astronomy DOI: 10.1051/0004-6361:20011364 & c ESO 2001 Astrophysics Can stellar winds account for temperature fluctuations in H II regions? The case of NGC 2363 V. Luridiana1,2,M.Cervi˜no3, and L. Binette2 1 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching b. M¨unchen, Germany 2 Instituto de Astronom´ıa, Universidad Nacional Aut´onoma de M´exico, Ap. Postal 70-264, 04510 M´exico D.F., Mexico 3 Max-Planck-Institut f¨ur extraterrestrische Physik, Gießenbachstraße, 85748 Garching b. M¨unchen, Germany Received 13 August 2001 / Accepted 25 September 2001 Abstract. We compare the rate of kinetic energy injected by stellar winds into the extragalactic Hiiregion NGC 2363 to the luminosity needed to feed the observed temperature fluctuations. The kinetic luminosity asso- ciated to the winds is estimated by means of two different evolutionary synthesis codes, one of which takes into account the statistical fluctuations expected in the Initial Mass Function. We find that, even in the most favorable conditions considered by our model, such luminosity is much smaller than the luminosity needed to account for the observed temperature fluctuations. The assumptions underlying our study are emphasized as possible sources of uncertainty affecting our results. Key words. Hiiregions – ISM: individual (NGC 2366, NGC 2363) – stars: clusters 1. Introduction For a long time, the only way temperature fluctua- tions were accounted for in theoretical models was ac- The presence of temperature fluctuations in photoionized knowledging the impossibility to reproduce the observed regions has been a matter of debate since the pioneer- intensity of the most affected lines; see, e.g., Luridiana ing work by Peimbert (1967). -
Cold Gas and Baryon-Induced Dark Matter Cores in Nearby Galaxies
Cold gas and baryon-induced dark matter cores in nearby galaxies Flor Allaert Supervisors: Prof. Dr. Maarten Baes, Dr. Gianfranco Gentile A dissertation submitted to Ghent University in partial fulfilment of the requirements for the degree of Doctor of Science: Astronomy September 2017 Supervisors: Prof. Dr. Maarten Baes Vakgroep Fysica en Sterrenkunde Universiteit Gent Dr. Gianfranco Gentile Vakgroep Fysica en Sterrenkunde Vrije Universiteit Brussel Jury members: Prof. Dr. Dirk Poelman (President) Vakgroep Vastestofwetenschappen Universiteit Gent Dr. Karel Van Acoleyen (Secretary) Vakgroep Fysica en Sterrenkunde Universiteit Gent Prof. Dr. Sven De Rijcke Vakgroep Fysica en Sterrenkunde Universiteit Gent Prof. Dr. Herwig Dejonghe Vakgroep Fysica en Sterrenkunde Universiteit Gent Prof. Dr. Uli Klein Argelander-Institut fur¨ Astronomie Universitat¨ Bonn Prof. Dr. Erwin de Blok Netherlands Institute for Radio Astronomy Contents 1 Introduction1 1.1 Galaxies - building blocks of the Universe.................1 1.1.1 Classification............................2 1.1.2 Chemical evolution.........................4 1.1.3 Accretion and mergers.......................6 1.2 Observing the different components....................8 1.2.1 Stars................................8 1.2.2 Gas.................................9 1.2.3 Dust................................. 12 1.3 Panchromatic SED modelling and dust radiative transfer......... 13 1.3.1 SED fitting............................. 13 1.3.2 Dust radiative transfer....................... 14 1.3.3 The energy balance problem.................... 15 1.4 FRIEDL, HEROES and NHEMESES................... 17 1.4.1 The energy balance problem revisited............... 18 1.5 Dark matter................................. 18 1.5.1 History............................... 19 1.5.2 Dark matter in cosmology..................... 21 1.5.3 Cosmological simulations..................... 23 1.5.4 The cusp-core controversy..................... 24 1.5.5 Baryons to the rescue?...................... -
Statistics and Properties of Emission-Line Regions in the Local
Mon. Not. R. Astron. Soc. 000, 000–000 (0000) Printed 27 April 2020 (MN LATEX style file v2.2) Statistics and Properties of Emission-Line Regions in the Local Volume Dwarf Galaxies I. D. Karachentsev1⋆, S.S.Kaisin1† 1Special Astrophysical Observatory of the Russian Academy of Sciences, Nizhnij Arkhyz, KChR, 369167, Russia 27 April 2020 ABSTRACT We used the Hα images from a large sample of nearby late-type dwarf galaxies to investigate properties of their emission structure. The sample consists of three hundred galaxies of the irregular (Irr), Magellanic irregular (Im), blue compact dwarf (BCD), and transition (Tr) types situated within a distance of 11 Mpc. In each galaxy, we indicated: the number of compact HII-regions, the presence of bubble-like or filament-like structures, the presence of a faint diffuse emission, and a sign of the global burst. The larger luminosity of a galaxy, the greater number of compact HII-sources in it. The integral and specific star-formation rates of the dwarf increase steeply with the increase of the number of HII-regions showing the evidence of the epidemic character of star-formation process. The dwarf galaxies with emission-line bubbles, or filaments, or signs of the global star-formation burst have approximately the same hydrogen-mass-to-luminosity ratio as that of the whole sample objects. arXiv:2004.11550v1 [astro-ph.GA] 24 Apr 2020 However, their mean star-formation rate is significantly higher than that of other galaxies in the sample. Emission bubble-like structures are found in the nearby dwarfs with a frequency of 1 case per 4-5 galaxies. -
Una Aproximación Física Al Universo Local De Nebadon
4 1 0 2 local Nebadon de Santiago RodríguezSantiago Hernández Una aproximación física al universo (160.1) 14:5.11 La curiosidad — el espíritu de investigación, el estímulo del descubrimiento, el impulso a la exploración — forma parte de la dotación innata y divina de las criaturas evolutivas del espacio. Tabla de contenido 1.-Descripción científica de nuestro entorno cósmico. ............................................................................. 3 1.1 Lo que nuestros ojos ven. ................................................................................................................ 3 1.2 Lo que la ciencia establece ............................................................................................................... 4 2.-Descripción del LU de nuestro entorno cósmico. ................................................................................ 10 2.1 Universo Maestro ........................................................................................................................... 10 2.2 Gran Universo. Nivel Espacial Superunivesal ................................................................................. 13 2.3 Orvonton. El Séptimo Superuniverso. ............................................................................................ 14 2.4 En el interior de Orvonton. En la Vía Láctea. ................................................................................. 18 2.5 En el interior de Orvonton. Splandon el 5º Sector Mayor ............................................................ 19 -
Sn2002kg and SN1954J in NGC 2403*
The Astrophysical Journal, 848:86 (13pp), 2017 October 20 https://doi.org/10.3847/1538-4357/aa8a71 © 2017. The American Astronomical Society. All rights reserved. A Tale of Two Impostors: SN2002kg and SN1954J in NGC 2403* Roberta M. Humphreys1 , Kris Davidson1, Schuyler D. Van Dyk2 , and Michael S. Gordon1 1 Minnesota Institute for Astrophysics, 116 Church St. SE, University of Minnesota, Minneapolis, MN 55455, USA; [email protected] 2 Caltech/IPAC, Mailcode 100-22, Pasadena, CA 91125, USA Received 2017 July 28; revised 2017 September 1; accepted 2017 September 1; published 2017 October 17 Abstract We describe new results on two supernova impostors in NGC 2403, SN 1954J(V12) and SN 2002kg(V37). For the famous object SN 1954J, we combine four critical observations: its current SED, its Hα emission line profile, the Ca II triplet in absorption in its red spectrum, and the brightness compared to its pre-event state. Together, these strongly suggest that the survivor is now a hot supergiant with T∼20,000 K, a dense wind, substantial circumstellar extinction, and a G-type supergiant companion. The hot star progenitor of V12ʼs giant eruption was likely in the post-red supergiant stage and had already shed a lot of mass. V37 is a classical LBV/S Dor variable. Our photometry and spectra observed during and after its eruption show that its outburst was an apparent transit on the HR Diagram due to enhanced mass loss and the formation of a cooler, dense wind. V37 is an evolved hot 6 supergiant at ≈10 L with a probable initial mass of 60–80 M. -
Surface Brightness Fluctuation Distances for Nearby Dwarf Elliptical
A&A 380, 90–101 (2001) Astronomy DOI: 10.1051/0004-6361:20011408 & c ESO 2001 Astrophysics Surface brightness fluctuation distances for nearby dwarf elliptical galaxies? H. Jerjen1,R.Rekola2, L. Takalo2, M. Coleman1, and M. Valtonen2 1 Research School of Astronomy and Astrophysics, The Australian National University, Mt Stromlo Observatory, Cotter Road, Weston ACT 2611, Australia 2 Tuorla Observatory, University of Turku, V¨ais¨al¨antie 20, 21500 Piikki¨o, Finland Received 12 July 2001 / Accepted 2 October 2001 Abstract. We obtained deep B and R-band CCD images for the dwarf elliptical (dE) galaxies DDO 44, UGC 4998, KK98 77, DDO 71, DDO 113, and UGC 7356 at the Nordic Optical Telescope. Employing Fourier analysis technique we measure stellar R-band surface brightness fluctuations (SBFs) and magnitudes in 29 different fields of the galaxies. Independent tip of the red giant branch distances for DDO 44, KK98 77, DDO 71 are used to convert their set of apparent into absolute SBF magnitudes. The results are combined with the corresponding local (B −R) colours and compared with the (B −R)−M R relation for mainly old, metal-poor stellar populations as predicted by Worthey’s population synthesis models using Padova isochrones. While the colour dependency of the theoretical relation is confirmed by the empirical data, we find a systematic zero point offset between observations and theory in the sense that models are too faint by 0.13 (0.02) mag. Based on these findings we establish a new semiempirical calibration of the SBF method as distance indicator for dE galaxies with an estimated uncertainty of ≈10%. -
Arxiv:Astro-Ph/0104091V1 4 Apr 2001 B .J Asnrsac Etr Obx28 Okonheight Yorktown 218, Box PO Center, Research Watson J
Neutral Hydrogen and Star Formation in the Irregular Galaxy NGC 2366 Deidre A. Hunter Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, Arizona 86001 USA; [email protected] Bruce G. Elmegreen IBM T. J. Watson Research Center, PO Box 218, Yorktown Heights, New York 10598 USA; [email protected] and Hugo van Woerden Kapteyn Astronomical Institute, Postbus 800, 9700 AV Groningen, The Netherlands; [email protected] ABSTRACT We present deep UBVJHKHα images and HI maps of the irregular galaxy NGC 2366. Optically, NGC 2366 is a boxy-shaped exponential disk seen at high inclination angle. The scale length and central surface brightness of the disk are normal for late-type galaxies. Although NGC 2366 has been classified as a barred Im galaxy, we do not see any unambiguous observational signature of a bar. There is an asymmetrical extension of stars along one end of the major axis of the galaxy, and this is where the furthest star-forming regions are found, at a radius of 1.3 times the Holmberg radius. The star formation activity of the galaxy is dominated by the supergiant H ii complex NGC 2363, but the global star formation rate for NGC 2366 is only moderately elevated relative to other Im galaxies. The star formation activity drops off with radius arXiv:astro-ph/0104091v1 4 Apr 2001 approximately as the starlight in the inner part of the galaxy but it drops faster in the outer part. There are some peculiar features of the HI distribution and kinematics. First, the integrated HI shows two ridges running parallel to the major axis that when deprojected appear as a large ring. -
Structure in the Neutral Hydrogen Disk of the Spiral Galaxy, IC
THE ASTRONOMICAL JOURNAL, 119:1720È1736, 2000 April ( 2000. The American Astronomical Society. All rights reserved. Printed in U.S.A. STRUCTURE IN THE NEUTRAL HYDROGEN DISK OF THE SPIRAL GALAXY IC 342 LUCIAN P. CROSTHWAITE AND JEAN L. TURNER Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095; lucian=astro.ucla.edu, turner=astro.ucla.edu AND PAUL T. P. HO Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138; pho=cfa.harvard.edu Received 1999 September 30; accepted 2000 January 7 ABSTRACT We present 38Aresolution Very Large Array 21 cm continuum and H I line emission observations of the spiral galaxy IC 342, at an adopted distance of 2 Mpc. Kinematic evidence exists for a m \ 2 spiral density wave in the inner disk with a corotation radius located at 4 kpc and a possible four-arm pattern in the outer disk. On smaller scales, outside of the central depression in H I column density, H I is organized into a complex pattern of relatively short (D2È5 kpc), interconnected, spiral arm segments. Numerous ““ holes ÏÏ are distributed throughout the H I disk. By considering the e†ects of shear, structures that are not self-gravitating, such as holes and voids, cannot be long-term phenomena. The timescale, combined with the total energy required to evacuate holes, leads us to reject wind and supernovae origins for the large-scale pattern of H I holes in IC 342. Gravitational instabilities in the disk form on a timescale that is short compared with the rotation period of the disk.