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Producing Science with the Palomar Transient Factory

Producing Science with the Palomar Transient Factory. Branimir Sesar (MPIA, formerly Caltech). Producing Science with the Palomar Transient Factory. Branimir Sesar (MPIA, formerly Caltech). Survey Goals & Key Projects (Law et al. 2009, Rau et al. 2009).

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Producing Science with the Palomar Transient Factory

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  1. Producing Science with the Palomar Transient Factory Branimir Sesar (MPIA, formerly Caltech)

  2. Producing Science with the Palomar Transient Factory Branimir Sesar (MPIA, formerly Caltech)

  3. Survey Goals & Key Projects(Law et al. 2009, Rau et al. 2009) Goal: to study the transient and variable sky Extragalactic Transients in nearby galaxies, CC SNe, TDE, Hα Sky Survey, search for eLIGO/EM counterparts Galactic AM CVn systems (H + He WD), CVs, RR Lyrae stars to map the Milky Way structure and dynamics Solar System: KBOs, smallNEAs/PHAs (prospect for growth → asteroid retrieval mission)

  4. P60 Photo. followup P48 wide-field imager → Discovery engine P200 Spec. followup

  5. Fast spectroscopic typing with SED Machine (R~100, PI: Nick Konidaris, Caltech) P60 Photo. followup P200 Spec. followup P48 wide-field imager → Discovery engine R~100 spectra of various transients and variables → important spectral features are still discernible

  6. P48 Overview 7.26 deg2 field-of-view → will be upgraded to 47 deg2 for ZTF (2015-2016) 1” / pixel resolution → barely sampled at median 2” seeing → PSF photometry possible Robotic telescope & scheduler → automatic selection of fields → time & money saver g', R, and 2 Hα filters ~250 images / night CFHT12k camera (well-defined cosmetics)

  7. Real-time Pipeline (transients) PTF Image Differencing Engine (PTFIDE; Frank Masci, IPAC)

  8. Real-time Pipeline (transients) 0.3% contamination, 0.7% of real transients missed Time from exposure to alert: 20 – 40 min

  9. IPAC Pipeline (variables & light curves) coverage of the Galactic plane (|b| < 5 deg) • Repeatability of < 0.01 mag • R-band 5σ limit @ 20.6 mag (aperture), 20.9 mag (PSF) • 12,000 deg2 with >30 epochs • 1st PTF/iPTF data release (M81, M44, M42, Cas A, Kepler) http://www.ptf.caltech.edu/page/first_data_release • Public release of PTF, iPTF and ZTF data (w/ NSF funding)

  10. Science • 2,254 spectroscopically confirmed SNe • 88 publications (5 in Nature) • Finding dSphs with PTF SN Ia in M101 (PTF11kly; Nugent et al. 2011, Li et al. 2011)

  11. Hundreds of low-luminosity dSph galaxies orbiting the MW? LSST should be able to observe ~300 low-luminosity dSphs About 50 low-luminosity dSphs in ~10,000 sq. deg and between 60 - 100 kpc Estimated number of observable faint MW satellites Tollerud et al. (2008) Low-luminosity dSph

  12. Segue I (MV = -1.5, D = 23 kpc, rh = 30 pc) Seg RGB → orange Seg MS → blue BHB RR Lyrae Only 6 RGB stars! MSTO

  13. “Segue I”-like dSph at 60 kpc (MV = -1.5) dSph RGB → orange foreground → white

  14. Segue I (MV = -1.5, D = 23 kpc, rh = 30 pc) Seg RGB → orange Seg MS → blue BHB RR Lyrae Only 6 RGB stars! MSTO

  15. Table 4 of Boettcher, Willman et al. (2013) Almost every dSph has at least one RR Lyrae star → use distant RR Lyrae stars as tracers of low-luminosity dSphs Boo III 1 -2.0 (Sesar, submitted to ApJ) Boo II 1? ? (within 1.5' of Boo II @ 33 kpc)

  16. ~180 RRab stars between 60 and 100 kpc Orange – Sgr?

  17. “Segue I”-like dSph at 60 kpc dSph is still invisible in the color-magnitude diagram

  18. Pick a distant RR Lyrae star D = 60 kpc

  19. Select stars that may be at the distance of the RR Lyrae star M92 isochrone at 60 kpc

  20. Plot angular coordinates with respect to the coordinates of the RR Lyrae star

  21. Convert angular to projected distances

  22. Repeat for a different RR Lyrae star (i.e., sightline) and add onto the same plot

  23. Repeat for a different RR Lyrae star (i.e., sightline) and add onto the same plot

  24. Overdensity of sources when fdSph = 1.0 ... Note: This is just for visualization

  25. ...when fdSph = 0.2

  26. … when f = 0 (i.e., just the background)

  27. Sensitivity of the detection method 123 98 74 Minimum number of dSphs needed for a detection 49 37 27 19 Black pixels: parameter space where detection is possible at 3-sigma level

  28. What is observed in SDSS

  29. Constraining the luminosity function of dSph galaxies rh = 120 pc rh = 30 pc

  30. PanSTARRS1 S82 light curve PS1 light curve PS1 is deeper than PTF, and covers more area → repeat search

  31. RR Lyrae Stars Old, evolved stars (> 9 Gyr) → trace old populations of stars Standard candles → identify them → know their distance (with ~6% uncertainty) Bright (V ~ 21 at 110 kpc) Variablestars (P ~ 0.6 day) with distinct light curves ( ~1 mag amplitude) → easily identifiable Repeated observations (~30 or more) are needed Light curve of an RR Lyrae type ab

  32. Death throes - An outburst from a massive star 40 days before a supernova explosion (Ofek+ 2013) Explosion! Outburst! No detection @ -60 & -50 days

  33. Localization of an optical afterglow in 71 deg2 (Singer et al. 2013) ZTF will cover this area with ~2 images Optical afterglow

  34. GRB 130702A to iPTF13bxl Timeline 00:05 Fermi GMB trigger (UT July 2nd) 01:05 position refined by human (GBM group) 03:08 Sun sets at Palomar 04:17 PTF starts observations (10 fields, 2x60-s per field; 72 square degrees) 4214 "candidates": 44 were known asteroids, 1744 were coincident with stars (r<21) → 43 viable candidates Human inspection reduced this to 6 excellent candidates iPTF13bxh core of a bright galaxy, iPTF13bxr known quasar, iPTF13bxt was close to a star in SDSS Remaining candidates: iPTFbxl(RB2=0.86), iPTFbxk (RB2=0.83) and iPTFbxj (RB2=0.49) Sunrise in California

  35. GRB 130702A to iPTF13bxl Timeline 00:50 Swift observations for iPTF13bxl requested (UT July 3rd) → X-ray source detected 04:10 Robotic observations of these candidates at P60 → iPTFbxl showed decline relative to first P48 observation (!) 04:24 Spectral observations on the Palomar 200-inch → spectrum is featureless (!!) 08:24 Announced iPTF13bxl as afterglow (ATEL, GCN) 17:34 LAT localization (3.2 square degrees) 19:03 IPN announces annulus of width 0.9 degrees 23:17 Magellan observations led to z=0.145

  36. Small, but potentially hazardous asteroids Adam Waszczak (grad student @ Caltech) NEA 2014 JG55 (diameter: 10 m, closest approach: ¼ Earth-Moon distance)

  37. RR Lyrae stars in SDSS Stripe 82 (Sesar, Ivezić+ 2010) “Smooth” inner halo ends at 30 kpc → only streams and dSphs beyond 30 kpc?

  38. Be Aware of the Contamination Sesar et al. (2007): Smaller number of epochs in SDSS Stripe 82 Could not properly remove non-RR Lyrae stars ~30% contamination in our RR Lyrae sample Detection of false halo substructures Psc

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