The Census of Planetary Nebulae in the Local

The Census of Planetary Nebulae in the Local Group Romano L. M. Corradi Isaac Newton Group of Telescopes, La Palma Laura Magrini Dip. di Astronomia, Universita’ di Firenze

The census of planetary nebulae in the Local Group Romano L. M. Corradi Isaac Newton Group of Telescopes, La Palma Laura Magrini Dip. di Astronomia, Universita’ di Firenze

An overview of the Local Group (LG) galaxy M 31 Milky Way M 33 LMC SMC M 32 NGC 205 IC 10 NGC 6822 NGC 185 IC 1613 NGC 147 WLM Sagittarius Fornax Pegasus Leo I* type log LV D (kpc) Sb 10. 43 760 Sbc 10. 31 Sc 9. 51 795 Ir 9. 35 50 Ir 8. 79 60 E 2 8. 55 760 Sph 8. 51 760 Ir 8. 47 660 d. Ir 8. 35 500 Sph 8. 19 660 d. Ir 8. 07 725 Sph 7. 99 660 d. Ir 7. 71 925 d. Sph 7. 47 24 d. Sph 7. 19 138 d. Ir 6. 87 760 d. Sph 6. 71 250 And II Leo A DD 210* Sag. DIG Pegasus. II Pisces And V And III Leo II Phoenix Sculptor Cassiopeia Tucana Sextans Carina Draco Ursa Min d. Sph d. Ir d. Sph d. Sph 6. 67 6. 55 6. 47 6. 23 6. 19 6. 11 6. 03 5. 99 5. 87 5. 75 5. 71 5. 39 5. 35 *data 810 700 690 1025 1300 830 810 760 210 395 87 690 870 86 100 79 63 not reduced yet

At the outer fringes of the LG… GR 8 d. Sph 6. 59 NGC 3109 d. Ir 8. 27 Antlia d. Sph 6. 33 Sextans B d. Ir 7. 67 Sextans A d. Ir 7. 63 EGB 0427+63* d. Ir 6. 31 2200 1360 1330 1320 1450 2200 possible physical association Beyond the LG, the IC 342/Maffei group, the South Polar (Sculptor) group, the M 81 group… Is the LG ultimately going to merge into an elliptical galaxy with approximately the luminosity of the Milky Way? Van den Bergh 2000, “The Galaxies of the Local Group”

Imaging searches for PNe in the LG • Baade (1955): 5 PNe in M 31 • ~100 PNe in LMC and SMC (see Westerlund 1968) • In the 70’s, Ford and collaborators detected a large number of PNe in M 31 (bulge) and a few ones in its companions • Jacoby & Lesser (1981) found PNe in 5 galaxies of the LG • Ciardullo et al. (1989): 429 PNe in M 31 • Magrini et al. (2000): 134 PNe in M 33 • Jacoby & De Marco (2002): deep survey of SMC • Merrett et al. (2003): 2611 PNe in M 31 with the P. N. S. • the “Local Group Census” (2001 -2004): 14 galaxies searched

The Local Group Census (LGC) It is a narrow- and broad-band imaging survey of the galaxies of the LG observable from La Palma (Dec>-30 ). J. Beckman, M. Bryce, A. Cardwell, R. Corradi, P. Crowther, R. Greimel, A. Herrero, M. Irwin, P. Leisy, D. Lennon, A. Mampaso, L. Magrini, M. Perinotto, R. Peletier, D. Pollacco, S. Prins, I. Skillen, S. Smartt, L. Smith, J. Telting, E. Tolstoy, J. Walsh, N. Walton, A. Zijlstra, A. Zurita Collaborators: ING, IAC, Open Univ. , Univ. of Amsterdam, ESO, Univ. of Firenze, Univ. de Granada, Institute of Astronomy Cambridge, Jodrell Bank, Univ. of Manchester, Queens Univ. Belfast, Univ. College London, Univ. of Nottingham, Univ. of Oxford, Univ. of Victoria, UMIST Institutions:

The LGC observations Instrumentation: Wide Field Camera of the 2. 5 m Isaac Newton Telescope (mosaic of four 4 k 2 k CCDs, f. o. v. 34 34 arcmin 2). Filters and exposure times: [OIII] (500. 8/8 nm), Ha+[NII] (656. 8/10), [SII] (672. 5/8), He. II (468. 6/10) Stromgren Y Sloan g, r, i 60 min (24. 5 mag) 30 min 20 min (25, 24) PNe search methods: • visual search of point-like sources in the [OIII] and Ha+[NII] continuum-subtracted images • [OIII]-g vs. Ha-r color-color diagrams

[OIII]-g vs. Ha-r color-color diagrams [OIII]-g NGC 205 Ha-r

The LGC observations The observations have basically being completed during a total of some 40 clear nights (out of 50 allocated). Details can be found at http: //www. ing. iac. es/~rcorradi/LGC Datasets are mostly reduced and public

PNe in the Milky Way subgroup 3 PNe 1 PN Danziger et al. 1978 Ap. J 220, 458 talk of G. Jacoby Zijlstra & Walsh 1996 A&A 312 L 21 poster by Zijlstra & Gesicki

PNe in the M 31/M 33 subgroup Jacoby & Lesser 1981 AJ 86 185 Magrini et al. 2000 A&A 355 713 Corradi et al. 2004 A&A in prep Ciardullo et al. 1989 Ap. J 339 53

M 31 Halliday et al. 2003 IAU Symp 219 p. 629 1284 PNe (717 new) in 3. 6 deg 2 ~2700 PNe talk of H. Merrett

IC 10 16 PNe Magrini et al. 2003 A&A 407 51

Magrini et al. 2003 A&A 407 51 1. 3 x 1. 1 kpc 2. 5 kpc huge HI envelope 12 x 15 kpc (Huchtmeier 1979 A&A 75 170)

PNe in “free-floating” galaxies of the LG NGC 6822 20 PNe WLM 1 PN IC 1613 3 PNe Leo A 1 PN talk of P. Leisy Magrini et al. 2004 MNRAS in prep ” “ “ Jacoby & Lesser 1981 AJ 86 185 Magrini et al. 2003 A&A 407 51

NGC 6822

WLM

IC 1613

Leo A

PNe at the outer fringes of the LG Sextans B 5 PNe Magrini et al. 2002 A&A 386 869 Sextans A 1 PN Magrini et al. 2003 A&A 407 51 NGC 3109 18 PNe GR 8 0 PN talk of L. Magrini Prada et al. 2004 in preparation Magrini et al. 2004 MNRAS in prep

Summary: n. of PNe in the Local Group galaxies Galaxy log LV n. PNe magc O/H 9. 0 M 31 10. 43 ~2700 Milky Way 10. 31 ~2000 8. 7 M 33 9. 51 134 2. 6 8. 4 LMC 9. 35 277 8. 35 SMC 8. 79 105 6 8. 03 M 32 8. 55 30 2. 4 8. 29 NGC 205 8. 51 35 3. 5 8. 6 IC 10 8. 47 16 2. 0 8. 2 NGC 6822 8. 35 20 3. 5 8. 25 NGC 185 8. 19 5 2. 7 7. 9 IC 1613 8. 07 3 7. 71 NGC 147 7. 99 9 <4. 4 WLM 7. 71 1 7. 78 Sagittarius 7. 47 3 8. 35 Fornax 7. 19 1 7. 98 Pegasus 6. 87 1 7. 93 Leo A 6. 55 1 3. 0 7. 36 Galaxy NGC 3109 Sextans B Sextans A log LV n. PNe magc 8. 27 18 7. 67 5 3. 0 7. 63 1 1. 9 O/H 7. 63 8. 12 7. 55

Observed population size vs. galaxian luminosity M 31 Milky Way LMC M 33 SMC M 32 I 10 N 3109 Sex. B Sagittarius Leo A Pegasus N 185 N 147 Sex. A I 1613 Fornax N 205 N 6822

PNe as tracers of intermediate-age populations Magrini et al. in prep. log (mass of intermediate-age stars) N(PNe) Relative SFR 2 -8 Gyrs 0. 2 Mateo 1998 ARAA 36, 435 Relative SFR 2 -8 Gyrs < 0. 2 log (total mass) van den Bergh 2000

Age effects? Same luminosity, morphology, and metallicity NGC 185 NGC 147 NGC 185 gas-rich and <1 Gyr star-formation in its centre NGC 147 gas-free, no SF in the last 3 Gyrs Mendez & Soffner 1997 A&A 321, 898 Marigo et al. 2004 A&A in press (strong see talk of P. Marigo (mild age effect on M*) effect for recent star formation)

NGC 185 Martinez-Delgado et al. 1999 AJ 118 2229 significant SF <1 Gyr very little SF 1 -3 Gyr some SF 1 -3 Gyr

NGC 185 Corradi et al. 2004 A&A in prep. significant SF <1 Gyr SF burst <0. 15 Gyr

Metallicity effects: the brightest PN metallicity correction Dopita et al 1992 AJ 389 27 But mixed with population size effects!

Summary • PNe have been searched (found) in all LG galaxies with log. LV>6. 7 • Their population size correlates well with the V luminosity of the galaxy, and in particular traces differences in the relative contribution of intermediate-age populations (2 -8 Gyr). Deeper searches are needed to strenghten this result • LG PNe are valuable indicators of: • metallicity (see talks/posters Richer, Magrini, Leisy, Stasinska, Perinotto, Kniazev, Maciel) • kinematics (see talk of Merrett for M 31, Durrell et al. 2002 AAS 201 1311 for M 33) • intergalactic light (IC 10, NGC 6822) • The effect of star formation in the last 1 -2 Gyr on the absolute magnitude of the bright cutoff of the PN luminosity function remains controversial. Possible positive evidence (e. g. NGC 185 vs. NGC 147) is weakened by the small PN population size in most LG galaxies