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Atomic gas (HI) in Isolated Galaxies. Daniel Espada Fernández Advisor: Lourdes Verdes-Montenegro Dpto. de Astronomía Extragaláctica IAA-CSIC. 3- HI study of isolated galaxies. Overview. 1- Introduction to the AMIGA project. 2- The sample of isolated galaxies. 4- Work in the future.

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Atomic gas hi in isolated galaxies

Atomic gas (HI) in Isolated Galaxies

Daniel Espada Fernández

Advisor: Lourdes Verdes-Montenegro

Dpto. de Astronomía Extragaláctica

IAA-CSIC


Overview

3- HI study of isolated galaxies

Overview

1- Introduction to the AMIGA project

2- The sample of isolated galaxies

4- Work in the future


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


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


1 introduction of the amiga project
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



2 the sample of isolated galaxies
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)


2 the sample of isolated galaxies1
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.


3 hi study of isolated galaxies
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


3 1 hi content

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


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


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


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


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


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


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


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


3 2 hi profile asymmetry

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!


3 2 hi profile asymmetry1

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


3 2 hi profile asymmetry2

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…)


3 2 hi profile asymmetry3

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


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


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


4 work in the future
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.





Status of the project
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


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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