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Help Desk: [email protected]. Mid-Cycle Proposals: http://www.stsci.edu/hst/proposing/mid-cycle- submission. WFC3 Main Page: http://www.stsci.edu/hst/wfc3.
C.M.  (Ka?e)  Gosmeyer,  P.R.  McCullough,  S.  BaggeK,  E.  Sabbi   Space  Telescope  Science  Ins.tute,  Bal.more,  MD  

Poster 416.14

cgosmeyer @stsci.edu

New  Mid-­‐Cycle  Proposal  Scheme  

Abstract   We provide a summary of new Wide Field Camera 3 (WFC3) capabilities and updates to the Hubble Space Telescope (HST) proposal process of interest to exoplanet observers. In particular, we discuss recent studies on high precision photometry with spatial scanning that show up to 0.1% photometric repeatability for the UVIS channel and 0.5% for the IR channel. We describe a new IR sample sequence, SPARS5, which may open up more orient ranges and scheduling opportunities for exoplanet targets. Finally we present a new mid-cycle proposal scheme for HST that will allow observers to apply for up to 5 orbits outside the standard annual call for proposals; this will be especially advantageous for observers of recently discovered exoplanets.

High  Precision  Photometry  with  UVIS  and  IR  Spa?al  Scanning   Absolute Photometry

Differential Photometry (referred to star C) σ = 0.19%

σ = 0.36%

Scanning rationale: More pixels (than staring mode): = more photons per exposure (and per HST orbit) = less Poisson noise = less uncalibrated systematics

ETC  Now  Supports  Spa?al  Scanning  Modes  

C

C

B O M

σ = 0.32%

M

C

σ = 0.21%

C

B

B

O

O M

M

IR finder chart. The 1st and 4th scans of each visit are shown, for horizontal scans (top) and vertical scans (bottom). Note that we purposefully shifted each scan to expose “fresh” pixels to the star light; this was to avoid self-persistence effects. IR: Flux ratios of stars (colors) to their respective means versus visit number. There are 4 visits and 4 exposures per visit. We scanned both horizontally (top) and vertically (bottom), and present both Absolute and Differential results (columns). Stars C, B, M, and O (see finder chart) are known to vary less than 0.1% from the K2 photometry of Vanderberg (2015). The rms (sigma) of points is indicated, excluding the values for the reference star (1.00 by definition) in the differential photometry. We continue to investigate the systematic variations in the absolute photometry, both inter-visit (jumps) and intra-visit (slopes).

References  &  Resources

 

McCullough, P.R, & Gosmeyer, C.M. 2015, WFC3 ISR-xx, in progress McCullough, P. R. 2015, A New Infrared Sample Sequence: SPARS5, WFC3 STAN Issue 20 Vanderburg, A. 2015, private communication

   

§  The WFC3 Exposure Time Calculator (ETC) will include spatial scanning modes for both UVIS and IR imaging, and IR grisms. §  Will go live by the Cycle 24 Call for Proposals. §  See etc.stsci.edu §  If you find problems, please contact the STScI Help Desk [email protected]

B

O

Help Desk: [email protected]

§  The new Mid-Cycle program will enable a quick turn-around for high-impact, but not necessarily time-critical proposals. Newly discovered exoplanets are an ideal case in this scheme. §  This is unlike Director’s Discretionary Time (DDT), which is often used for time-critical events such as comets and supernovae. §  Mid-Cycle GO proposal criteria (in short): •  Provide explanation why proposal could not be submitted for the standard annual Call for Proposals. (I.e., target exoplanet was discovered after annual proposal deadline.) •  Provide description of scientific urgency of the observations. •  Limited to 5 orbits or less. •  Minimal constraints to maximize scheduling flexibility. •  Propriety period of no more than 3 months. §  Submission period for Mid-Cycle is between August 2015 and 31 January 2016. Submissions after 1 February 2016 will be considered in the Cycle 24 TAC review. §  For more detailed information, see handout or use QR code.

UVIS results (not shown) are easier to report: Poisson limited performance of absolute photometry down to a systematic noise floor of ~0.1% caused by unknown effect(s). (We suspect shutter timing jitter but this is unproven at this time.)

Mid-Cycle Proposals: http://www.stsci.edu/hst/proposing/mid-cyclesubmission WFC3 Main Page: http://www.stsci.edu/hst/wfc3 WFC3 Instrument Handbook: http://www.stsci.edu/hst/wfc3/documents/handbooks/ currentIHB/wfc3_cover.html

WFC3 Data Handbook: http://www.stsci.edu/hst/wfc3/documents/handbooks/ currentDHB/wfc3_cover.html

SPARS5  Sample  Sequence §  Intermediate between RAPID and SPARS10. §  Short cadence to better isolate a target exoplanet from a stellar companion in spatially scanned IR grism observations, allowing a wider range of orients and increased scheduling opportunities. §  Ideal for G141 and G102 grism observations of stars brighter than ~7 mag in H band, scanned at >1 arcsec/ sec. §  First science observations successfully implemented in September 2015.

GRISM256

GRISM512

Readout

RAPID

SPARS5

SPARS10

RAPID

SPARS5

SPARS10

0

0.0000

0.0000

0.0000

0.0000

0.0000

0.0000

1

0.2805

0.2805

0.2805

0.8605

0.8530

0.8605

2

0.5610

2.6294

7.6296

1.7210

3.7745

8.7896

3

0.8414

4.9784

14.9788

2.5814

6.6960

16.7188

4

1.1219

7.3274

22.3279

3.4419

9.6175

24.6479

5

1.4024

9.6763

29.6771

4.3024

12.5391

32.5771

6

1.6829

12.0253

37.0262

5.1629

15.4606

40.5062

7

1.9634

14.3742

44.3754

6.0234

18.3821

48.4354

8

2.2438

16.7232

51.7245

6.8838

21.3036

56.3645

9

2.5243

19.0722

59.0737

7.7443

24.2251

64.2937

10

2.8048

21.4211

66.4228

8.6048

27.1466

72.2228

11

3.0853

23.7701

73.7720

9.4653

30.0681

80.1520

12

3.3658

26.1190

81.1212

10.3258

32.9896

88.0812

13

3.6462

28.4680

88.4703

11.1862

35.9111

96.0103

14

3.9267

30.8170

95.8195

12.0467

38.8326

103.9395

15

4.2072

33.1659

103.1686

12.9072

41.7541

111.8686

Comparison of readout times (sec) of different sample sequences for the subarray apertures most used in exoplanet spectroscopy (GRISM256 and GRISM512). Adapted from McCullough (2015).

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