Planetary Nebulae and HII as probes of the evolution of Local Group galaxies

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Planetary Nebulae and HII as probes of the
evolution of Local Group galaxies

• A.Y. Kniazev (SAAO),
• S.A. Pustilnik (SAO),
• E.K. Grebel (ARI)
• and many others ...

SAO RAS
14 September 2009
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Plan

• Introduction Reasons to study extragalactic
  PNe/HII
• Examples of some nearby dIrr galaxies PNe and
  HIIs
• PNe in M31 with SDSS data
• The method of using SDSS data
• New M31 PNe
• Sample of PNe in M31
• Andromeda NE as progenitor of stream

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HII Regions

HII regions are regions where active
star-formation in galaxies is currently located
(gas is heated by massive stars).
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Planetary Nebulae (PNe)

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HII\PN

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Some reasons to study extra-galactic PNe/HII (1)?
PNe/HII as chemical probes of galaxies
the
emission lines can provide nebular abundances
for PNe - related to those
of the progenitor star
for HII - ISM from which massive stars were
formed.

• PN in Fornax dSph (Distance 140 kpc)
  
  V18.9 mag 2x30 min with NTT 3.5m telescope
  O, Ar, N,
  Ne, S, Cl, Fe, He and C with accuracy 0.02
  0.20 dex
  
• PN in Sextans A (Distance 1400 kpc)
  
  V22.4 mag 3x30 min with NTT
  O,
  Ar, N, S, He with accuracy 0.05 0.25 dex
  
• 2 stars (V17.3 mag) from NGC6822 (Distance
  490 kpc) 3x1 h for each
  with 10m Keck telescope
  O, Si, Sc, Ti,
  Cr, Fe, Ni with accuracy 0.1- 0.3 dex

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HII/PNe as chemical probes


Maciel, Lago Costa (2006, AA, 453, 587)?
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Some reasons to study extra-galactic PNe/HII (2)?

• PNe/HII as kinematic probes
  (1) since
  PNe are just ordinary stars that we happen to
  catch at the ends of their lives,
  they are fairly representative of
  the bulk stellar population of the galaxy
  (2) HII regions - hot
  gas
  
• PNe as a secondary distance indicator
  photometry of
  the O III ?5007 Å emission line showed that
  the luminosity function of the PN population
  in a galaxy has a characteristic shape.

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Examples of PNLF

Herrmann et al. (2008 ApJ, 683, 630)?
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Sextans A
From Kniazev et al. (2005, AJ, 130,1558)?
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Sextans B
From Kniazev et al. (2005, AJ, 130,1558)?
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Sextans A and B
Kniazev et al (2005) Magrini et al. (2005)
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IC10
dIrr IV/BCD Distance 550 - 980 Mpc 16 PNe
candidates from Magrini et al. (2003)?

7 PNe candidates were observed with 6m SAO RAS
telescope in 2004,2006 altogether with many HII
regions
9 additional PNe candidates were found by
Magrini Consalves (2009) In the central area
5x5 arcmin

30x30 arcmin ?
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PNe in IC10 (SFH)
Taking into account - all observed PNe in IC10
are stars formed 7-10 Gyr ago - amount of PNe
is proportional to the total mass of stars
was born during of certain epoch - PN relates
to 2106 Msun ??
SFR 0.02-0.04 Msun/year during 7-10 Gyr ago
The best fir of SF history for the HST field
from Zucker (2001).
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Sloan Digital Sky Survey (SDSS)?

• Imaging in drift-scan mode (ugriz)?
• Spectroscopic (R 2000) survey -
  all galaxies up to r17.77 -
  QSOs
• Data are processed and located in the
  database
• Covers gt1/4 of the sky.

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SDSS Observations of M31
From Dan Zucker

• Data obtained 5 October 2002 (Runs 3366 and 3367)
  in 3 hours
• Two overlapping strips oriented along the major
  axis of M31, covering an area of 18x2.5

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SDSS Stellar Density Distribution
(1) Stellar structure 3 to NE (2) At
approximately same distance as M31 (3) Radius
30' (4) ?0,V 28.6 and MV -12.4 (5)
Satellite or stream? (6) Can have 0.5 2 PNe
From Zucker et al. (2004)
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Emission Objects with SDSS
Is it possible to select PNe candidates using
SDSS data?
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Selection Criteria for PNe candidates
Identification of PNe from Nolthenius Ford
(1987) and from Jacoby Ford (1986) 30 were
identified with position accuracy lt 1?

• We then applied all these criteria to the whole
  area of M31 as scanned by SDSS
• We also applied the same selection criteria to
  extended objects (90 at r 21.6)?
• All selected candidates were visually verified
  for the false selections (difraction spikes)
• Finally, we selected 230 PNe candidates
  102 PNe candidates of the first priority
  and 128 PNe candidates of the second
  priority

From Kniazev et al. (2009a, in preparation)
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PNe canidates in the Outer Part of M31
Candidates positions traced different
substructures of outer part of M31
3 candidates in the area of Andromeda NE have
been found !!!
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Spectral follow-up Observations(1)?

• 2.2m telescope at Calar Alto (Spain)
• CAFOS 42007800 Å, 1.9 Å/pix
• 8 nights in October 2004 under variable weather
  conditions
• 1530 min exposures
• Totally 80 candidates from 230 were observed
  with efficiency of 88 for our method

The selection method is very efficient !
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Last decade M31

Deep panoramic survey with the Isaac Newton
Telescope (2.5m) Wide Field Camera (0.29
sq.deg)? ( Ferguson et al. 2002) V and i
filters Keck DEIMOS multiobject spectrograph
(in total 2800 stars) Ibata et al. (2005)
Wide-field camera of CFHT (Ibata et al. 2007)? g
and i filters
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Last decade PNe in M31
(1) December 2004 - Hurley-Keller et al.
(2004) 136 PNe selected with narrow-band imaging
and observed with WIYN Hydra fiber
spectrograph (2) Halliday et al. (2006) 723
PNe in the disk and bulge narrow-band imaging
and spectroscopy with fibre-fed spectrograph at
WHT (LA Palma)? (3) Merret et al. (2006) 2615
PNe selected with PN.S at WHT

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Velocity distribution with PNe
Some PNe were identified by Merrett et al. (2003,
2006) as a possible continuation of the merging
Southern Stream of stars (Ibata et. 2001,2004)
No HI in the region of And NE
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Is And NE the core or remnant of the progenitor
of this stream ?
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Spectral Observations of selected PNe

• 3.5m telescope at Calar Alto (Spain)
• TWIN 35007500 Å, 1 Å/pix
• (FWHM 5Å)
• 4 (3) nights in August 2005 under variable
  weather conditions
• Total exposures 4560 min
• Totally 9 PNe were observed
• 6m telescope (SAO Russia)
  SCORPIO 3700-7200 Å, 2.5 Å/pix
• 1 additional PN in Andromeda NE

From Kniazev et al. (2009b, in preparation)
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And NE is the core or remnant of the progenitor
of the stream (1)?
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How bright was And NE before? (1)?
In total 22 PNe are selected as members of this
stream

M(V) -15.9
Was comparable to NGC205!
From Magrini et al. (2003)?
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How bright was And NE before? (2)?
From LZ ratio for dEs

M(B) -15.8
Was comparable to NGC205!
gt 90 of stars was lost?
From Kunth Ostlin et al. (1999)?
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Model
From Fardal et al. (2007, MNRAS, 380, 15)
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The End

The End