HST Archival Studies of HH 30 WFPC2 Data Retrieval and Reduction Liu, Jimmy Chun-Fan Supervisor: Dr. Shang, Hsien August 23, 2002 Summer Student Program 2002 Oral Presentation

August 23, Outline HH 30 ： The Herbig-Haro Object HST Archive Overview WFPC2 ： The Instrument Performance Data Reduction Studies based on “Hubble Space Telescope Observation of the Disk and Jet of HH 30”, Burrows et al, ApJ , Dec 1996

August 23, The Herbig-Haro Objects Nebulosities with high speed relative to the surroundings. Cataloged independently by G. Herbig and G. Haro in the early 1950’s. Now is extended to a protostellar system with jets.

August 23, A.U.

August 23, “My” Object － HH 30 RA : 4 h 31 m 37 s.60 Dec : +18:12' 26".0 Constellation : Taurus Distance ～ 140 pc Extension in the sky : 5' NNE (1995) ; 3' SSW (1990) WHY we choose HH30 ?

August 23, © Lisa Chien 5º5º Accretion Disk “Counterjet” Reflection Nebulosities Jet Protostar Why the Shape ? Observer

August 23, HST Archive Search Quick guide 1.Register a one-year-valid account. 2.Search for what you need from searching form. 3.Mark the datasets you want for scientific use. 4.Choose the method of retrieving data (via ftp is a good choice in IAA). 5.Receive letter regarding data storage status. 6.Retrieve datasets via anonymous ftp (ftp archive.stsci.edu).

August 23, HST Archive Search Form Web-based Search Form: archive.stsci.edu/cgi-bin/hst/ archive.stsci.edu/cgi-bin/hst/ –Handy and convenient. StarView: A software handling dataset search and retrieval. –The search criteria can be more specified.

August 23, HST Archive Search Specify object name Radius from the specified object Exposure time The data can only be publicly accessible after this date The “color” of the image can be chose

August 23, What to Retrieve ? “Cleaned” data Calibrating files Raw data Calibrated data Pipeline Calibration (According to CCD properties) Data Reduction (Cosmic Rays, CCD performance) Recalibrate myself Data Analysis Prepare for Data Reduction

August 23, Question: How do we go from to ? Before… After… Or Furthermore … M16 － The Eagle Nebula ©STScI

August 23, Wavelength specified by “Filter” Why WFPC2 (pronounced as WiFPiC-2) ? NICMOS 20355Å WFPC2 5047Å WFPC2 7940Å Processed using PowerPoint by Lowering Brightness and Lifting Contrast

August 23, The Wide-Field and Planetary Camera 2 4 camera combined: 800×800 pixels –PC: " per pixel ＞ Higher resolution for planets –WF2,3,4: " per pixel ＞ Wide filed of view CCD Performance: –QE: 14% in the red (peak) –A-to-D gain (5 or 7 e - /DN) –Read noise: 5~6 electrons Camera Performance –Undersampling WF2 WF4 PC WF3 1'1'

August 23, Undersampling: What and Why ? What ? –70% of the starlight hit the ONE center pixel –Stars look extremely sharp in the CCD Why ? –Pixel too large: technique limit –Point Spread Function (PSF) too narrow: GOOD seeing in the space! Why should I care ?

August 23, Data Reduction Procedure for WFPC2 Using Image Reduction and Analysis Facilities (IRAF) developed by NOAO Cosmic rays rejection Warm pixels fixing Streaks (due to charge trapping of CCD)

August 23, Cosmic rays Cosmic rays or faint stars? “dark” streak Star and “bright” streak

August 23, Cosmic Ray “Pick-up” Strategy Many images with sub-pixel offset –Dithering (dividing pixels) Many images with the same field of view and the same exposure time –crrej task of IRAF/STSDAS What if I only have ONE single frame? –cosmicrays task in IRAF/STSDAS –other method suggested (e.g. edge detection, etc.)

August 23, Datasets Regarding the Paper 1994 data F555W 5407Å; 350sec exposure 1 image F675W 6714Å; 120sec exposure 1 image F814W 7940Å; 60sec exposure 1 image –Try cosmicrays task 1995 data F675W 6714Å; 800sec exposure 2 images F814W 7940Å; 1200sec exposure 2 images –Use crrej task

August 23, The 1994 Data Results (F555W)

August 23, U2KY0101T U2KY0102T Please compare these two images Two Exposures of 1995 at 6714Å

August 23, The 1995 Data Results (F675W) Trial 1 Trial 5

August 23, Comparison with Paper Burrows et al, 1996

August 23, Future Work Deconvolution of the images Data analysis: reproduce Burrows’ results –Photometry of the knots –Astrometry (position, proper motion, etc) Further data analysis from different cameras of HST

August 23, Acknowledgement Dr. Shang for guideline and project direction. Drs. Andrew Wang and S-Y Wang for CCD knowledge. Dr. Yen and Mr. Hsieh for IRAF discussions. Computer Guys for problem solving! Mei-Yin and Hsin-Lun for help and discussions. Summer Students for mutual supports. Our “baby-sitters”: Dr. King and Ken Chen! And others who helped me in IAA.