Morphological classification of new candidate PNe in an IPHAS sample

Kerttu Viironen

IAC

Collaboration: A. Mampaso (IAC) R. Corradi (ING, IAC), R. Greimel (Cambridge), L. Sabin (IAC) IPHAS collaboration

Overview:

1) PN morphology; introduction

2) IPHAS survey

3) Searching for PNe from IPHAS data

3) Morphology of the PN candidates at 18h-20h

PN morphology; introduction

- PNe present various morphologies:- Elliptical, Bipolar, Point-Symmetric,

Irregular, Stellar (Schwarz et al. 1992; classes author dependent)

- Morphology connected to - abundances (bipolars overabundant in He, N; Corradi & Schwarz 1995)

- location in Galaxy (median galactic latitude increase from bipolars to ellipticals and to rounds; Manchado & Villaver 2000)

- central star properties (bipolars more massive progenitors; Corradi & Schwarz 1995)

- All this should be explained theoretically; constraints the theories

IPHAS survey

ING, La Palma: Corradi, Leisy, Lennon, Skillen

UK: Aungwerojwit (Warwick), Barlow, Hales, Wright (UCL), Drew (PI), Unruh (Imperial), Evans (ATC), Gaensicke (Warwick), Greimel, Irwin, Walton (IoA), Knigge, Witham (Southampton), Morris, Phillipps (Bristol), Vink (Keele), Zijlstra (Manchester)

Spain (IAC): Mampaso, Martin, Rodríguez-Flores, Rodríguez-Gil, Sabin, Viironen

The Netherlands (Nijmegen): Groot, Morales-Rueda, van den Besselaar

USA (CfA): Drake, Sokoloski & Steeghs (CfA)

Australia (AAO/Macquarie): Parker

Collaboration:

IPHAS survey

IPHAS = the INT/WFC Photometric H Survey of the Northern Galactic Plane

Area: all l in Northern Plane; –5° < b < +5° (1800 deg2)

Mag. limit: ~ 20 in r’

Observations: 2.5m Isaac Newton Telescope (La Palma) + Wide Field Camera (4-CCD mosaic, 2048x4200 pix, fov 34x34 arcmin2, 0”.33 pix-1)

H (120 sec), Sloan r’ (30 sec) and i’ (10 sec) at two closely overlapped pointings per field

IPHAS survey

A map of the sky: IPHAS survey area shown in green

IPHAS surveyAnalysis: Pipeline reduction and point-source photometric and

astrometric catalogue generation by CASU.

IPHAS data are available immediately to astronomers from UK, Spain and the

Netherlands, and to ALL astronomers after 1 year from the date of observing.

IPHAS web page:

http://www.iphas.org

IPHAS overview: Drew et al. 2005, MNRAS , 362, 753

Other IPHAS related papers: see the IPHAS webpage!

Search techniques:

1. Semi-automatic technique: photometric catalogue (r’-H colors) compact/small nebulae

2. visual inspection of mosaics medium/large nebulae

- There are about 2000 PNe known in the Galaxy- Several hundreds are expected to be found by IPHAS- IPHAS goes deep → faint and/or distant PNe explored

The PN search

Shiode et al. 2006IPHAS

The PNe search; compact PNe

E(B-VE(B-V))

Drew et al. 2005

main sequence

giants

supergiants

Synthetic photometrySynthetic photometryconstructed using constructed using Pickles (1998) libraryPickles (1998) libraryof flux-calibrated of flux-calibrated stellar spectrastellar spectra

r’-H

r’-i’

The PNe search; compact PNe

Known PNe in IPHAS two-color diagram

The PNe search; compact PNe

- Noise and saturated objects filtered out as well as the detection close to the borders of the CCDs or areas of bad pixels

- Objects should be detected at least in Hα and r’ (matching distance 1 arcsec)

- Object should be detected at least twice

- The magnitude in Hα < 19.5

The PNe search; compact PNeFinal selection made visually (so far only 18h-20h region complete!)

810 studied

613 studied, M

(Hα) < 17

not studied

Automatically selected objects at 18h-20h + known PNe

Total: 56314 objects

The PNe search; extended PNe

Visual search from IPHAS r’ – Hα mosaics:

- 15 x 15 pixel binning for

lowest surface brightness nebulae

- 5 x 5 pixel binning for

intermediate size nebulae

The three methods overlap →

more complete

Candidate PNe in the IPHAS area at 18h – 20h region:

389 objects found

100 of these are known PNe

289 new candidate PNe

- 133 with “clear morphology”

→ considered in the morphological study

- 37 unresolved/barely resolved)

Morphology of the PNe/PN candidates

Elliptical66%

Bipolar14%

P-Symm.0%

Irregular20%

Corradi & Schwarz 1995 (359 southern PNe):

Our study (133 candidate PNe in the galactic plane):

Elliptical64%

Bipolar14%

P-Symm.4%

Irregular18%

Morphology of the PNe/PN candidates

Round58%

Elliptical25%

Bipolar17%

Manchado & Villaver 2000 (<255 PNe in the galactic plane):

Round28%

Elliptical59%

Bipolar13%

Our study (133 PNe in the galactic plane):

Conclusions

- IPHAS is greatly increasing the number of

northern Galactic PNe

- We find a new faint round PNe population in the galactic plane

Thank You!

The PNe search; compact PNe

Final selection made visually

810 studied

613 studied, M(Hα) < 17

not studied

Known PNe in IPHAS two-color diagramIPHAS area;18h – 20h region