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Harvard-Smithsonian 0 Center for Astrophyslcs - Harvard-Smithsonian 0 Center for Astrophyslcs Preprint Series No. 4621 (Received November 19, 1997) THE EVOLUTION OF GAS AND STARS IN THE MERGER GALAXY NGC 1316 (FORNAX A) G. Mackie and G. Fabbiano Harvard-Smithsonian Center for Astrophysics To appear in Astronomical Journal February 1998 HARVARD COLLEGE OBSERVATORY SMITHSONIANASTROPHYSICALOBSERVATORY 60 Garden Street, Cambridge, Massachusetts 02138 An X-ray Catalog and Atlas of Galaxies by G. Fabbiano, D-W. Kim, and G. Trinchieri, Ap.J.Suppl. 1992, 80, 531-644. The X-ray spectra of Galaxies: I. Spectral Fits of Individual Galaxies and X-ray Colors by D-W. Kim, G. Fabbiano, and G. Trinchieri, Ap.J.Suppl. 1992, 80, 531. The X-ray Spectra of Galaxies: II. Average Spectral Properties and Emission Mechanisms by D-W. Kim, G. Fabbiano and G. Trinchieri, Ap.J. 1992, 393, 134. Prepints are attached. *A Multiparametric Analysis of the Einstein Sample of Early-type Galaxies. II: Galaxy Formation History and Properties of the ISM by P. Eskridge, G. Fabbiano, and D-W. Kim, Ap.J. 1995, 442, 2. *A Multiparametric Analysis of the Einstein Sample of Early-type Galaxies. III: Compar- isons with the t_ Parameters, Ap.J. 1995, 448, 7-. *ROSAT PSPC Observations of NGC 507/499: Central Cooling and Mass Determination, by D-W. Kim, and G. Fabbiano, Ap.J., 1995, 441,182. *ROSAT PSPC Observations of Two Dynamically Young Elliptical Galaxies: NGC 4125 and NGC 3610 by G. Fabbiano and F. Schweizer, Ap.J. 1995, 447, 572. ASCA Spectra of the X-ray Faint SO Galaxy NGC 4382 by D-W. Kim, G. Fabbiano, H. Matsumoto, K. Koyama, and G. Trinchieri, Ap.J. 1996, 468, 175. ROSAT PSPC Observations of NGC4636: Interaction with Virgo Gas? by G. Trinchieri, D-W. Kim, G. Fabbiano, and C. Canizares, Ap.J. 1994, 428, 555. *ROSAT PSPC Observations of two X-ray faint Early-type Galaxies: NGC 4365 and NGC 4382 by G. Fabbiano, D-W. Kim, G. Trinchieri, and C. Canizares, Ap.J. 1994, 429, 94. *The very soft X-ray emission of X-ray faint early-type galaxies by S. Pellegrini and G. Fabbiano, Ap.J. 1994, 429, 105. *Detection of Soft X-rays from SN 1993J Six Days after Outburst NATURE 1994, 367, 621. X-ray Properties of Early-type Galaxies by G. Fabbiano, ESO proc. of the Elba Conference (J. Danziger , W.W. Zeilinger and K. Kjar, eds.), ESO proc. No. 45, p.617. Coronal Stellar Emission in Galaxies by G. Fabbiano, in Physics of Solar and Stellar Coro- nae: G.S. Vaiana Memorial Symposium (J. F. Linsky and S. Serio, eds; Kluwer) 1993, p. 267. Normal Galaxies and their X-ray Binary Populations by G. Fabbiano, to appear in "X-ray Binaries" (W. Lewin, J. van Paradijs, and E. van den Heuvel, eds; Cambridge Univ. Press), 1995. X-ray continuum and iron K emission line from the radio galaxy 3C 390.3 by M. Inda, K. Makishima, Y. Kohmura, M. Tashiro, T. Ohashi, P. Barr, K. Hayashida, G.G.C. Palumbo, G. Trinchieri, M. Elvis, and G. Fabbiano, Ap.J. 1994, 420, 143. High Resolution Optical and UV Observations of the Centers of NGC 1316 and NGC 3998 by G. Fabbiano, C. Fassnacht, and G. Trinchieri, Ap.J. 1994, 429, 94. *The insignificance of "Heating flows" in "cooling flow" clusters of galaxies by C.R. Canizares, T.H. Markert, Sera Markoff, and J.P. Hughes, Ap.J.Lett. 1993, 405, 17. This grant was instrumental on supporting a number of researchprojects, including the analysis of archival Einstein data, and ROSAT and ASCA observations.Highlights of this work include: • The final production and publication of the Einstein galaxy catalog, resulting in a databaseof 450 galaxiesobservedin X-rays. X-ray spectral surveyof galaxiesobservedwith Einstein, whichshowedclear trends in galaxiesof different morphology, pointing to different sourcesof the X-ray emission. This work also led to the discoveryof different spectral propertiesin X-ray faint and X-ray bright E and SO,which was then followed up by ourselvesand other authors with many ROSAT and ASCA papers. Multiwavelength correlation analysesof the Einstein E and SOsample,which pointed out the combinedeffectof potential depth and shapein the galaxy'sability of retaining an extendedhot gaseoushalo. Multiwavelength correlationanalysesof the Einstein Spiral andIrregular sample. This work waspart of the SeniorThesisof A. Shapley,a Harvardundergraduate,nowa grad- uate student in Caltech. This work waspresentedin a poster at the AAS Washington meeting (Jan 1998),and is beeingwritten up in three papersfor publication. Investigations of the X-ray properties of X-ray faint galaxies,with both ROSAT and ASCA. This work clearly shows different spectral properties which we interpret as evidenceof complexemission,including both the integratedemissionof discreteX-ray sources,and a gaseouscomponentin somecases.We also pointed out the possibility of a population of very soft soft sourcesin thesegalaxies. • Investigation of the X-ray properties of X-ray bright galaxies,wherethe emission is dominated by hot extendedhalos,which can be usedto measurethe galaxy's mass. A list of significant papersproducedunder support of this grant is given below. *indicates paper previouslysupplied. The Evolution of Gasand Stars in the Merger Galaxy NGC1316(Fornax A) by G. Mackie and G. Fabbiano, Ap.J., Feb 1998. ROSAT X-ray Observationsof the Radio Galaxy NGC1316(Fornax A) by D-W. Kim, G. Fabbiano,and G. Mackie, Ap.J. 1998. *A Multiparametric Analysisof the Einstein Sample of Early-Type Galaxies. I. Luminosity and ISM Parameters by P. Eskridge, G. Fabbiano, and D-W. Kim, Ap.J.Supp. 1995, 97, 141-184. The Evolution of Gas and Stars in the merger galaxy NGC 1316 (Fornax A) G. Mackie 1 and G. Fabbiano Harvard.Smithsonian Center for Astrophysics, 60 Garden S_ree_, Cambridge, MA 0_188 ABSTRACT We present optical and archival X-ray data on the disturbed morphology radio ellip- tical NGC 1316 (Fornax A) that displays numerous low surface brightness shells, loops and tails. An extended (81x27" or 9x3 kpc) emission line region (EELR) at a projected distance of 35 kpc from the nucleus has been discovered in a ,,,90x35 kpc, ,-,3.0x109 LB® tidal tail. The position and extreme size of the EELR suggest it is related to the merger process. We suggest that the ionization mechanism of the EELR is shock excitation, and the gas is remnant from the merger progenitor. X-ray emission is detected near two tidal tails. Hot, -,,5 x 10SK gas is probably the predominant gas component in the tidal tail ISM. However based on the current tidal tail (cold + warm + hot) gas mass, a large fraction of the tidal tail progenitor gas may already reside in the nucleus of NGC 1316. The numerous and varied tidal tail system suggests that a disk-disk or disk-E merger could have taken place > 1 Gyr ago, whilst a low mass, gas rich galaxy started to merge -,, 0.5 Gyr ago. Subject headings: galaxies: structure- galaxies: photometry- galaxies: peculiar- galaxies: individual- galaxies: interactions- X-rays: galaxies aVisiting Astronomer, Cerro Tololo Inter-Americ_u Observatory. CTIO is operated by AURA, Inc. under contract to the National Science Foundation. Center forAstrophysics PreprintSeriesNo. 4621 THE EVOLUTION OF GAS AND STARS IN THE MERGER GALAXY NGC 1316 (FORNAX A) G. Mackie and G. Fabbiano Harvard-Smithsonian Center forAstrophysics 1. Introduction ies of merger galaxies(eg. NGC 1275, Holtzman et al. 1992; NGC 7252, Whitmore et al. 1993; NGC 4038/9, NGC 1316 (Fornax A, PKS 0320-37, Arp 154) is Whitmore and Schweizer 1995). one of the closest, D = 22.8 Mpc (adopting v0=1713 The origin of tidal tails such as those seen in km s-1, Sandage and Tammann 1981, hereafter RSA, NGC 1316 is firmly established. Toomre and Toomre and H0 = 75 km s-1 Mpc -1) and brightest radio (1972) and Toomre (1977) proposed that gravita- galaxies in the sky. Its catalogue morphological type tional interactions between disk galaxies could form is uncertain, being described as Sa pec (merger?) in RSA. It is located on the outskirts of the Fornax clus- tidal features. Further, Toomre (1977) suggested that such disk-disk mergers could ultimately resemble el- ter, and is projected 3.70 from the centrally located lipticals. Theoretical studies of equal mass disk-disk cluster giant elliptical NGC 1399. Extensive opti- mergers by Barnes (1992) have strengthened the case cal observations of Schweizer (1980), hereafter $80, of a merger origin for some ellipticals, whilst recent and Schweizer (1081) show NGC 1316 (MB ",, -22.7) models (Barnes and Hernquist 1996) have included possessing a surprisingly small core radius and high gas dynamics showing that large central concentra- central surface brightness for its luminosity. These tions of gas can form in the cores of merger remnants. unusual Core properties alone may suggest a previ- Such predictions have been verified by the detection ous merger event (Kormendy 1087) has taken place. of large amounts of molecular gas in merger galaxies $80 showed NGC 1316 to be a D-type galaxy with such as NGC 520 (Sanders et al. 1988), NGC 4038/9 an elliptical-like spheroid surrounded by a large enve- (Stanford et al. 1990) and NGC 7252 (Dupraz et al. lope. Photographic plate imagery shows the envelope 1990). possessing numerous low surface brightness arcs or shells and loops, including a large loop that extends Multi-wavelength observations of mergers can pro- ~25' S-SW (,,-170 kpc adopting 9"/kpc) from the vide important constraints on the types of progeni- galaxy nucleus. Long-slit spectroscopy by $80 shows tors, the stellar and gaseous properties of tidal fea- tures and merger remnant and the ultimate fate of a rapidly rotating (vsinl -,-350 km s-1 ) disk of ionized gas in the centre of the galaxy with a rotation axis al- the remnant.
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