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Producing science with_ptf
1. Producing Science with the Palomar
Transient Factory
Branimir Sesar (MPIA, formerly Caltech)
2. Survey Goals
(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, Milky
Way structure and dynamics
• Solar System: KBOs, small asteroids (prospect for growth
→ asteroid retrieval mission)
4. P48 wide-field imager →
Discovery engine
P48 wide-field imager →
Discovery engine
P200
Spec. followup
P200
Spec. followup
P60
Photo. followup
P60
Photo. followup
Fast spectroscopic typing
with SED Machine (R~100,
PI: Nick Konidaris, Caltech)
Fast spectroscopic typing
with SED Machine (R~100,
PI: Nick Konidaris, Caltech)
R~100 spectra of various transients and variables
→ important spectral features are still discernible
R~100 spectra of various transients and variables
→ important spectral features are still discernible
5. 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
(some cosmetics, ghosts)
CFHT12k camera
(some cosmetics, ghosts)
8. IPAC Pipeline (variables & light curves)
• 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)
coverage of the Galactic plane (|b| < 5 deg)coverage of the Galactic plane (|b| < 5 deg)
9. Science
• 2,254 spectroscopically
confirmed SNe
• 88 publications (5 in
Nature)
SN Ia in M101 (PTF11kly;
Nugent et al. 2011, Li et al. 2011)
SN Ia in M101 (PTF11kly;
Nugent et al. 2011, Li et al. 2011)
10. An outburst from a massive star 40 days
before a supernova explosion (Ofek+ 2013)
No detection @ -60 daysNo detection @ -60 days
Outburst!Outburst!
Explosion!Explosion!
11. Localization of an optical afterglow in 71
deg2
(Singer et al. 2013)
ZTF will cover this area
with ~2 images
ZTF will cover this area
with ~2 images
12. 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
• 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
13. GRB 130702A to iPTF13bxl Timeline
• 00:50 Swift observations for iPTF13bxl requested → 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
14. Small, but potentially hazardous asteroids
Adam Waszczak
(grad student @
Caltech)
Adam Waszczak
(grad student @
Caltech)
NEA 2014 JG55 (diameter: 10 m, closest approach: ¼ Earth-Moon distance)NEA 2014 JG55 (diameter: 10 m, closest approach: ¼ Earth-Moon distance)
15. ~180 RRab stars between 60 and 100 kpc
Orange – Sgr?Orange – Sgr?
16. ΛCDM prediction: Hundreds of ultra-faint
dSph galaxies orbiting the MW
ultra-faint
dSph
ultra-faint
dSph
Tollerud et al. (2008)Tollerud et al. (2008)
Predicted number of observable
faint MW satellites
Predicted number of observable
faint MW satellites
• LSST should be able to
observe ~300 ultra-faint
dSphs
• About 50 ultra-faint dSphs
in ~10,000 sq. deg and
between 60 - 100 kpc
17. Segue I (MV
= -1.5, D = 23 kpc, rh
= 30 pc)
MSTOMSTO
RRcRRc
BHBBHB
Only 6
RGB stars!
Only 6
RGB stars!
Seg RGB → orange
Seg MS → blue
Seg RGB → orange
Seg MS → blue
18. “Segue I”-like ultra-faint dSph at 60 kpc
dSph RGB → orange
foreground → white
dSph RGB → orange
foreground → white
19. Segue I (MV
= -1.5, D = 23 kpc, rh
= 30 pc)
MSTOMSTO
RRcRRc
BHBBHB
Only 6
RGB stars!
Only 6
RGB stars!
Seg RGB → orange
Seg MS → blue
Seg RGB → orange
Seg MS → blue
20. 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)
• Variable stars (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 abLight curve of an RR Lyrae type ab
21. Table 4 of Boettcher, Willman et al. (2013)
Boo III 1 -2.0 (Sesar, submitted to ApJ)
Boo II 1? ? (within 1.5' of Boo II @ 33 kpc)
Boo III 1 -2.0 (Sesar, submitted to ApJ)
Boo II 1? ? (within 1.5' of Boo II @ 33 kpc)
22. “Segue I”-like ultra-faint dSph at 60 kpc
dSph RGB → orange
foreground → white
dSph RGB → orange
foreground → white
33. Sensitivity of the detection method
Black pixels: parameter
space where a detection
is possible
Black pixels: parameter
space where a detection
is possible
34. RR Lyrae stars in SDSS Stripe 82 (Sesar, Ivezić+ 2010)RR Lyrae stars in SDSS Stripe 82 (Sesar, Ivezić+ 2010)
“Smooth” inner halo ends at 30 kpc → only streams
and dSphs beyond 30 kpc?
“Smooth” inner halo ends at 30 kpc → only streams
and dSphs beyond 30 kpc?
35. 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
PscPsc