Coronagraphic Imaging of Protoplanetary Disks with HSTNICMOS HST GO 10177

1
Coronagraphic Imaging of Protoplanetary Disks
with HST/NICMOS(HST GO 10177)
A project status report by Sascha P. Quanz
PI Glenn Schneider (Steward Observatory) Th.
Henning, S. Wolf, K. Stapelfeldt, D. Padgett, C.
Grady, J.Krist, J. Kim, F. Menard, A. Cotera,
D. Hines, M. Silverstone,...
PSF Seminar June 8th 2005
2
Outline

• Introduction
• Knots and bolts of the data reduction
• First results
• Summary and Outlook

3
Outline

• Introduction
• Knots and bolts of the data reduction
• First results
• Summary and Outlook

4
Introduction

• Which objects are observed in the course of the
  program?
• Why is it interesting to observe them with
  HST/NICMOS?
• How are they actually observed?

5
Introduction (1)

• Which objects are observed in the course of the
  program?

52 science objects with spectral types A-M
6
Introduction (2)

• Why is it interesting to observe them with
  HST/NICMOS?

• Detailed morphology of circumstellar material
  (as close as 0.3)
• Physical properties of disks and nature and
  evolution of grains therein
• Only handful of (evolved) disks have been imaged
  in scattered light

GOAL Understanding formation process of
planetary systems !
7
Introduction (3)

• How are they actually observed?

• 52 science targets
• - Two coronagraphic images during one orbit
• - Intervening slew maneuver of telescope leads
  to 30 deg rotation between images
• - Filter F110W or F160W if disk already
  detected in other programs (WFPC2, STIS, ...)
• - Two direct images for flux calibration in
  the same filter
• 4 reference PSF stars (M0, K5, B8, A1)
• - also coronagraphic and direct imaging in
  one/both filter(s)

8
Outline

• Introduction
• Knots and bolts of the data reduction
• First results
• Summary and Outlook

9
Coronagraphic data... easy for bright disks
HR 4796A
HD 141569A (Herbig AeBe) 5 Myr
A 400AU radius disk, with a broad, partially
filled asymmetric gap containing a spiral
arclet.
HR 4796A (A0V), 8 Myr A 70AU radius ring, 12
AU wide ring of very red material
10
Coronagraphic data... can be tricky
The case of 55 Cancri...
(Trilling et al. 1998/2000)
(Schneider et al. 2001)
11
Data reduction... and its bottlenecks...
12
PSF scaling issues
Radial Profile
13
Data reduction... and its bottlenecks...
Alignment of the PSFs
Scaling of the PSFs
PSF Subtraction
Derive Flux densities
Create Model
14
PSF subtraction issues
Same target, various reference PSFs!
15
Data reduction Better be safe!

• Do not believe in a pipeline result! Do targets
  one by one!
• Double check scaling, e.g. by noise statistics
  in outer regions!
• Apply numerous reference PSFs and null-detection
  to match the science PSF
• Believe only what shows up in both roll
  orientation of the space telescope!

16
Outline

• Introduction
• Knots and bolts of the data reduction
• First results
• Summary and Outlook

17
First results (1)
DOAR 25
DL Tauri
HH30
3
To be confirmed!
4
GO Tau
18
First results (2)
RY Tau
0
DQ Tau
Clear scattered light detection Mostly
instrumental scattering?
3
3
30
19
Outline

• Introduction
• Knots and bolts of the data reduction
• First results
• Summary and Outlook

20
Summary

• Large HST/NICMOS program for coronagraphic
  imaging of 26 YSOs 26 Debris Disks is currently
  ongoing
• Data reduction is complicated (even
  more complicated than expected)
• First very promising/interesing results showed up

21
Outlook

• Data reduction Applying various PSF stars
• -gt residuals subtraction
• Derive flux densities for individual targets
  -gt from intrumental counts
  to mJy / arcsec2
• Combining results with other observations where
  possible, e.g., WFPC-2 GO Tau, DoAr 25 STIS DL
  Tau, DM Tau.
• Modelling

22

Thanks for your attention!