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Atomic gas (HI) in Isolated Galaxies

This project focuses on studying the atomic gas (HI) in isolated galaxies to understand the role of environment in galaxy formation and evolution. The sample of isolated galaxies is studied using multi-frequency observations to analyze their properties and interactions.

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Atomic gas (HI) in Isolated Galaxies

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  1. Atomic gas (HI) in Isolated Galaxies Daniel Espada Fernández Advisor: Lourdes Verdes-Montenegro Dpto. de Astronomía Extragaláctica IAA-CSIC

  2. 3- HI study of isolated galaxies Overview 1- Introduction to the AMIGA project 2- The sample of isolated galaxies 4- Work in the future

  3. Team Instituto de Astrofísica de Andalucía • Emilio García (System Manager) • Stéphane Leon (PostDoc) • Ute Lisenfeld (PostDoc) • Lourdes Verdes-Montenegro (Staff, P.I.) • José Sabater (PhD candidate) • Simon Verley (PhD candidate, IAA – Obs. Paris) • Daniel Espada (PhD candidate) International collaboration • Jack Sulentic – University of Alabama • Steve Odewahn – Arizona State University • Walter Huchtmeier – Max Planck Institute of Bonn • Min S. Yun – FCRAO • Soledad del Rio – INAOE AYA 2002-03338

  4. Instituto de Astrofísica de Andalucía Emilio García (System Manager) Stéphane Leon (PostDoc) Ute Lisenfeld (PostDoc) Lourdes Verdes-Montenegro (Staff, P.I.) José Sabater (PhD candidate) Simon Verley (PhD candidate, IAA – Obs. Paris) Daniel Espada (PhD candidate) International collaboration Jack Sulentic – University of Alabama Steve Odewahn – Arizona State University Walter Huchtmeier – Max Planck Institute of Bonn Min S. Yun – FCRAO Soledad del Rio – INAOE Françoise Combes – Paris Observatory Margarita Rosado – UNAM A. Bosma, L. Athanassoula (Obs. Marseille) M. Gutiérrez-Valdez (Univ. Guanajuato) I. Puerari (INAOE) A. Ballu (ENSP Strasbourg) Team AYA 2002-03338

  5. 1.Introduction of the AMIGA project -Motivation: • Role of the environment in the formation and evolution of galaxies • reference sample with minimum influence from the environment • properties of ISM as a function of isolation, and its relation to morphology, luminosities, star formation and nuclear activity. -Reference of isolated galaxies needed: Catalogue of isolated galaxies (CIG, Karachentseva 1973) -Multifrequency study: optical, FIR, NIR, Ha, CO, radiocontinuum, HI http://www.iaa.es/AMIGA.html

  6. http://www.iaa.es/AMIGA.html

  7. 2. The sample of isolated galaxies Isolation criterion (Karachentseva, 1973): A galaxy (diameter=d) is isolated if there isn’t any other galaxy (d’): • ¼ d < d’ < 4 d • Angular separation < 20 d’ • POSS-I plates • Northern hemisphere: dec > -3º • Optical magnitude: down to 15.7 (B band) • 1051 isolated galaxies • Revision (1980): 0 – Isolated (893) 1 – Marginally isolated (85) 2 – Member of a group or a cluster (64)

  8. 2. The sample of isolated galaxies a) Velocity: the CIG samples a deep enough volume of space to measure the radio, IR and optical luminosity functions; b) Blue luminosity: large range of luminosities; c) Morphology: the CIG is morphologically diverse to permit statistical studies correlated with Hubble type.

  9. 3. HI study of isolated galaxies Introduction -hiperfine transition of H, λ=21cm -provides information about : -content of atomic gas -kinematics -tracer of interactions Objectives: 3.1-HI content 3.2-HI profile asymmetries

  10. 3.Atomic gas 3.1 -HI content 1. LITERATURE • DENSER ENVIRONMENT: spirals in clusters are HI deficients (Van Gorkom et al 1996) and some of them are stripped until 90% of their HI (Haynes et al 1990). -> HI DEFICIENCY CAUSED BY INTERACTION • REFERENCES OF ISOLATED GALAXIES: Until now the best reference was Haynes et al 1984 = 324 isolated galaxies observed in HI; or field galaxies. 2. IMPROVEMENTS OF OUR STUDY OF IG • Quantity: -Doubles the number of gal. (lower dispersion in subsamples) • Quality: -Exhaustive bibliographic compilation • -Selection of the best profiles (extent/beam) • -repeat not satisfactory observations

  11. 3.Atomic gas 3.1 -HI content 4. COMPILATION OF DATA -100 articles -365 galaxies were already observed, selection of data, digitalization of profiles 5. OBSERVATIONS

  12. 3.Atomic gas 3.1 -HI content 4. COMPILATION OF DATA -100 articles -365 galaxies were already observed, selection of data, digitalization of profiles 5. OBSERVATIONS Effelsberg 100m, Germany. 155

  13. 3.Atomic gas 3.1 -HI content 4. COMPILATION OF DATA -100 articles -365 galaxies were already observed, selection of data, digitalization of profiles 5. OBSERVATIONS Effelsberg 100m, Germany. 155 GBT 100x110m, Green Bank,MA, USA 51

  14. 3.Atomic gas 3.1 -HI content 4.COMPILATION OF DATA -100 articles -365 galaxies were already observed, selection of data, digitalization of profiles 5. OBSERVATIONS Effelsberg 100m, Germany. 155 GBT 100x110m, Green Bank,MA, USA 51 NRT, Nançay ,France 129

  15. 3.Atomic gas 3.1 -HI content 4. COMPILATION OF DATA -100 articles -365 galaxies were already observed, selection of data, digitalization of profiles 5. OBSERVATIONS Effelsberg 100m, Germany. 155 GBT 100x110m, Green Bank,MA, USA 51 NRT, Nançay ,France 129 Arecibo 304m, Puerto Rico 34

  16. 3.Atomic gas 6. HI PROFILE EXAMPLE: CIG 661 POSSI GBT Radial velocity : 3341 +/- 9 km/s Diameters: 1.3 x 0.9 arcmin Magnitude : 15.1 Type: Sm Flux HI=S=6.05 +- 0.11 Jy km/s Width=220 km/s velocity HI= 3336+-10 km/s

  17. 3.1.HI content 3.Atomic gas S= integrated flux d25 = diameters (= Ø) D25 B = beam of the telescope 7. STATUS • 90% of the IG observed + 200 hours at Nancay. • 100% profiles calibrated & reduced for the IG observed, but not corrected for beam attenuation • Data available in the DB for the study: M(HI) = f(LB, Ø, t) Sc = Sc(D25,d25, B, t) = beam/extent corrected int. flux D = distance LB = Blue luminosity MHI= 2.36 105 D2 [Mpc] Sc[Jy km/s] t= type

  18. 3.Atomic gas 3.2.HI-profile asymmetry 1. LITERATURE a) OTHER SAMPLES OF ISOLATED GALAXIES N=104 Haynes et al 1998 N=30 Matthews et al 1998 b) OTHER ENVIRONMENTS -Clusters N=30 Sp Van Driel et al 1998 77% N=1700 Richter & Sancisi 1994 50 % (Visual examination) -Groups N=100 Sulentic & Arp 1983 most of asymmetric prof. are not isolated galaxies 50 % of them have asymmetric profiles!

  19. 3.Atomic gas F1 A= F2 3.2.HI-profile asymmetry 2. ASYMMETRY CALCULATIONS • Example of asymmetry coefficient: F F1 F2 vm V • Examples of real HI profiles: CIG421(asymmetric) & CIG736 (symmetric) A=1.01 A=1.13

  20. 3.Atomic gas 3.2.HI-profile asymmetry • First results: • -N=40 isolated galaxies • observed by us • -S/N>10 • Around 50 % of them • have asymmetric profiles • as in previous studies • (but N is small and not • reliable…)

  21. 3.Atomic gas 3.2.HI-profile asymmetry 3. EXPLANATIONS FOR LOPSIDENESS 1) Pointing offsets of the radiotelescope. 2) Confusion with companions within the radiotelescope beam. 3) Noncircular motions. 4) True distortions in the HI mass distribution. -Asymmetries in IG are caused by small HI-rich companions or are intrinsic to the isolated galaxy???. HI MAPS needed

  22. 3.2.HI-profile asymmetry 3.Atomic gas 4. “HI MAPS of IG” LITERATURE -D. J. Pisano ’s Thesis 2001, 41 “isolated galaxies” observed at VLA and ATCA to observe HI clouds down to MHI=10^7 13 of them had HI-rich companions… BUT -the isolation criteria wasn’t so restrictive as our -galaxies without z wasn’t taken into account

  23. 3.2.HI-profile asymmetry 3.Atomic gas 4. “HI MAPS of IG” LITERATURE -D. J. Pisano ’s Thesis 2001, 41 “isolated galaxies” observed at VLA and ATCA to observe HI clouds down to MHI=10^7 13 of them had HI-rich companions… BUT -the isolation criteria wasn’t so restrictive as our -galaxies without z wasn’t taken into account Observations at the VLA (proposed for the next season). Subsample: 10, with A>1.10, S/N>10, very isolated and beam/extent>2

  24. 4.Work in the future • Comparison with samples of galaxies in denser environments (groups). • Correlation with other comp. of the ISM and SF. Ex: MHI+H2 vs SF • HI content vs bars, AGNs. • Studies for a subsample of very isolated HI-rich galaxies with 2D-information (VLA). • Collaboration with SubMillimiter Array (SMA) in the calibration • of the interferometer, using CIG galaxies.

  25. http://www.iaa.es/AMIGA.html

  26. FIN

  27. C.Public database

  28. Status of the project • Isolation criteria:77 % of the POSS fields checked • LB y LFIR for the whole sample • 36 % H of the subsample observed • 67 % CO of the subsample observed or compiled • 85 % HI data has been observed or compiled • 80 % radio continuum reprocessed Vatican Observatory Summer School 2003

  29. Effelsberg 100m, Bonn,Germ. Arecibo 304m, Puerto Rico IAA-CSIC, Granada Nançay,France IRAM 30m, Granada Spain FCRAO 14m, Mass., USA

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