The Search for AM CVn Systems with the Palomar Transient Factory David Levitan Caltech in collabora>on with Paul Groot, Thomas Kupfer, Shri Kulkarni, Tom Prince and the PTF Collabora>on AM CVn Workshop April 16th, 2012 The SDSS Survey Anderson et al. (2005) Fig. 1.—SDSS discovery spectra of the four new AM CVn candidates, displayed with a five-point boxcar smoothing. Each candidate was discovered first in the
course of a visual examination of several hundred thousand SDSS spectra. Each spectrum is dominated by helium, and each shows double-peaked emission indicative of
a helium accretion disk.
−0.5
−0.4
−0.3
u� − g �
−0.2
−0.1
WD 0.0
Sloan Digital Sky Survey QSO 0.1
0.2
−0.5
−0.4
−0.3
−0.2
g� − r�
−0.1
0.0
High-­‐state Systems OutbursFng Systems Quiescent Systems 20 minutes 40 minutes Orbital Period !"#$%&'(%"& )%(* +%,-'. "$,/0+'(%"&, !"&,%,(/&(.1 ,*")/2 (*'( (*/
"-($-0,( 2/!'1/2 0'3%2.14 )%(* '& -&30/!/2/&(/2 0'(/ "5
678 #'9 2!:7 ;*/ '33.%!'(%"& "5 (*/ 3*',/ 2%,3/0,%"& #%&%#%<'(%"&
=>?@A #/(*"2 =B(/..%&9)/05 :C8DA4 '5(/0 0/#"+%&9 (*/ 0'3%2.1
2/!.%&%&9 (0/&24 0/+/'./2 (*/ '$,/&!/ "5 (*/ :ECFG, ,%9&'. =#%22./
3'&/.4 (*/ /H3/!(/2 ,%9&'. !"00/,3"&2%&9 (" ' 50/I-/&!1 "5
JD 2!:A7 ;*/ 3*',/G'+/0'9/2 .%9*( !-0+/ =.")/0 3'&/.A4 ',,-#%&9
(*/ :ECFG, 3/0%"24 '.," 5'%., (" ,*") (*/ 3/0%"2%! ,%9&'.7 K/ 5//.
(*'( )/ ,*"-.2 !"##/&( "& (*/ 2/(/!(%"& "5 ' .")G'#3.%(-2/
:ECFG, ,%9&'. %& (*/ .") ,('(/ $1 >0"+/&!'. /( '.7 =:CC8A7
L"&,%2/0%&9 (*'( (*/%0 "$,/0+'(%"& !"+/0/2 (*/ .'(/ ,('9/ "5 '
,-3/0"-($-0,( '&2 (*/ /'0.1 3",(G,-3/0"-($-0,( ,('9/4 %( %, &"(
,-030%,%&9 (*'( )/'M ,-3/0*-#3 ,%9&'., #'1 *'+/ /&,-/2 "+/0 '
."&9 3/0%"2 '5(/0 ' ,-3/0"-($-0,(7 N 9""2 /H'#3./ "5 3/0,%,(/&(
Photometric Variability ,-3/0*-#3 ,%9&'., ."&9 '5(/0 ,-3/0"-($-0,(, !'& $/ ,
:CCOP:CC8 ,-3/0"-($-0,( "5 QR L&! =/797 >'((/0,"& /(
S"0 !"#3'0%,"&4 S%97 D 2%,3.'1, (*/ ,'#/ '&'.1,%, 5"0
&%9*( 2-0%&9 (*/ $0%9*( ,('(/ =:CCO @'1 :EA4 )%(* '
./+/. ,%#%.'0 (" (*'( "5 :CCD T'&-'01 67 ;*/ #%22./ 3'&
!./'0 ,%9&'. '0"-&2 JC 2!:4 '&2 (*/ 3*',/G'+/0'9/2 .%9*
(*/ .")/0 3'&/. ,*"), ' 5-.. '#3.%(-2/ "5 F7FE #'9 5"0
,%9&'.7 K/ *'+/ (*-, !"&5%0#/2 (*'( (*/ :ECFG, ,%9&'.4
$/ (*/ U,-3/0*-#3V ,%9&'.4 %, &"( '33'0/&( 2-0%&9
"-($-0,(7 ;*%, %, '& %2/&(%51%&9 !*'0'!(/0%,(%! "5 ,-3/0*W@' (13/ 2)'05 &"+'/7 K/ *'+/ 5%0#.1 %2/&(%5%/2 (*/ ."
$0%9*( ,('(/ ', ' ,-3/0"-($-0,(4 '&2 (*/ ,*"0(G.%+/2 "
/H/#3.%5%/2 $1 (*/ :CCD T'&-'01 "-($-0,(4 ', ' &"0#'
.'!M%&9 .'09/G'#3.%(-2/ ,-3/0*-#3,7 LX Y"" %, ' *
Ostricker & Hesser (1968) Kato et al. (2000) !"#$%& )( Z$,/0+'(%"&, =,%&!/ :CC8A 5".2/2 '( (*/ ,-3/0!1!./ "5 EO7[ 27 \& (*/ 3/0%"2 "5 3*',/ F7FPF7J =%& (*/ ,-3/0!1!./ 3*',/A4 (*/ ,1,(/# 5'2/,
.%&/'0.14 ', %& BW W@' (13/ 2)'05 &"+'/ 2-0%&9 ,-3/0"-($-0,(7 \& (*/ 3/0%"2 "5 3*',/ F7JP:7F4 (*/ ,1,(/# ,*"), ,3'0,/ ,*"0( "-($-0,(,7
Light Curve of AM CVn Light Curve of CR Boo High-­‐state Systems Luminosity (3 known) OutbursFng Systems (15 known) Quiescent Systems (11 known) 20 minutes 40 minutes Orbital Period Why Outburst SelecFon? •  Color-­‐independent •  Surveys a (believed) different part of the AM CVn system populaFon •  Allows us to probe deeper (to 23rd mag!) •  Photometry does not need to be perfect •  A significant fracFon of the AM CVn lifeFme is believed to be spent in the outbursFng phase Palomar Transient Factory Palomar 48” Oschin Schmidt Telescope 7.26 deg2 FOV Palomar 200” Hale telescope Spectroscopic followup Palomar 60” Photometric followup + Follow-­‐up @ Collabora>on Observatories (i.e. Keck, Gemini, etc…) The PTF Field of View 92 MPix 1.0 arcsec sampling R=21 in 60 seconds The Transient Data Flow What happens at IPAC? Nightly Image Processing: Exposures “Standard” Reduc>on Calibra>on Final Nightly Products Second Level Products: Deep Reference Images Depth: 21.7 – 23.2 Source Matching < 0.1” precision at bright end 1.5” at faint end Rela>ve Photometry Photometric Performance R-­‐band Coverage: ∼15,000 deg2 with > ∼10 exp ∼8,000 deg2 with ≥ 30 exp g’-­‐band Coverage: ∼5,000 deg2 with > ∼10 exp ∼1,800 deg2 with ≥ 30 exp Many fields are covered daily Depth coverage: 14 < R < 20.6 14.5 < g’ < 21 Calibra>on is both absolute (to SDSS) and rela>ve PTF is one of the deepest, best-­‐calibrated synop>c surveys with large sky coverage Transient DetecFon 16
Magnitude (R)
17
18
19
20
21
0
0
d
= UT 2009 Nov 02
100
200
300
400
500
HJD − 2455138.0
Transient detecFon is best for faint systems that are seen in outburst only once But measurements only obtained when there is significant change in brightness Outburst DetecFon 16
PTFS1122aw
Magnitude
17
Brighter systems typically have solid detecFons in quiescence 18
19
20
21
22
0
20
40
60
80
100
120
140
HJD − 2454832.5
17
PTFS1109h
Magnitude
18
Fainter systems will only be observed in outburst – thus we need deep “reference” images 19
20
21
22
0
200
400
600
HJD − 2454832.5
800
1000
ClassificaFon Spectra Outburst light curve tells us liale more than that there is an outburs>ng system. Classifica>on spectra are necessary to iden>fy the type of system. PTF1 J071912.13+485834.0 Detected as Supernova candidate on 2009 December 01 ClassificaFon spectrum obtained as part of SN program IdenFfied as AM CVn system with addiFonal significant follow-­‐up P48 RelaFve Photometry Light Curve of PTF1J0719+4858 PTF1J0719+4858 Light Curve 15.2
P60
FTN
16.0
NO
16.8
NO
17.6
NO
18.4
Super
Outburst
Magnitude (g � )
19.2
0
10
20
30
40
50
60
0d = UT 2010 Oct 28
15.2
Normal
Outburst
(2011 Jan 29)
16.0
NO?
NO
16.8
Super
Outburst
17.6
NO?
18.4
Super
Outburst
(2011 Jan)
19.2
60
80
100
HJD − 2455497.0
120
140
Levitan et al. (2011) Orbital Period: 26.77 minutes Super-­‐outburst recurrence Fme: 65-­‐80 days Levitan et al. (2011) Source of AM CVn Photo. Variability Levitan et al. (2011) He I λ7065
He I λ6678
He I λ5876
He I λ5015
He I λ4921
0.9
He II λ4686
He I λ4387
1.0
He I λ4471
PTF11aab – High InclinaFon? 0.8
Normalized Flux
0.7
0.6
⊕
0.5
0.4
0.3
0.2
0.1
⊕
4000
4400
4800
5200
5600
Wavelength (Å)
6000
6400
6800
Levitan et al. (in prep) Detected in outburst, spectrum taken, shows emission lines in outburst! In CVs, this is indicaFve of high inclinaFon, but we have not seen any eclipses 0.7
0.6
PTF10noc R = 22.5 in quiescence 4000
4400
He II λ4686
He I λ4471
He I λ4387
0.2
He I λ4026
0.4
He II λ4200
0.5
0.3
4800
5200
5600
6000
6400
6800
Wavelength (Å)
0.9
0.8
Levitan et al. (in prep) He I λ6678
He I λ5876
1.0
PTF11dkq Only candidate now R = 23 in quiescence! 0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
4500
⊕
⊕
He II λ4686
Normalized Flux
He I λ7065
He I λ6678
0.8
He I λ3888
Normalized Flux
0.9
He I λ5876
He I λ4921
1.0
He I λ5015
PTF10noc and PTF11dkq 4800
5100
5400
5700
6000
Wavelength (Å)
6300
6600
6900
0.08
0.04
0.00
0.16
0.12
6000
4000
6300
4200
6600
He I λ4471
He I λ4387
He II λ4200?
He I λ4120
He I λ4144
He I λ4026
Ca II λ3968
Ca II λ3934
0.54
0.48
4400
6900
4600
0.28
0.24
7200
Wavelength (Å)
4800
⊕
7500
5000
Fe II λ5169
Fe II λ5192
He I λ5047
He I λ5015
He I λ4921
He II λ4686
He I λ4713
Fe II λ4629
Fe II λ4583
Fe II λ4549
0.60
NI
3800
He I λ7065
0.18
He I λ3888
0.24
He I λ6678
Si λ6347
Si λ6371
He I λ5876
Normalized Flux
PTF11avm 0.42
0.36
0.30
5200
7800
5400
0.32
Period is ~34 min 0.20
⊕
⊕
8100
Levitan et al. (in prep) PTFS1109h 17
Orbital period iden>fied as 30.35 min PTFS1109h
Magnitude
18
19
20
21
22
0
200
400
600
800
1000
HJD − 2454832.5
2.0
Orbital Phase
Ky (km s−1 )
1500
0
−1500
−1000
Levitan et al. (in prep) 0
Kx (km s
1000
−1
)
1.5
1.0
0.5
0.0
−1500
−750
0
750
Line velocity (km s
−1
)
1500
0.01
0.00
−0.01
3800
0.06
6000
4000
6400
4200
0.05
6800
NI
0.15
He I λ7065
0.20
He I λ4471
He I λ4387
He II λ4200?
He I λ4120
He I λ4144
He I λ4026
Ca II λ3968
Ca II λ3934
He I λ3888
0.25
He I λ6678
Si λ6347
Si λ6371
He I λ5876
Normalized Flux
0.50
0.45
4400
4600
0.04
7200
Wavelength (Å)
4800
7600
8000
Fe II λ5169
Fe II λ5192
He I λ5047
He I λ5015
He I λ4921
He II λ4686
He I λ4713
Fe II λ4629
Fe II λ4583
Fe II λ4549
PTFS1109h 0.40
0.35
0.30
5000
5200
8400
5400
⊕
⊕
⊕
0.03
0.02
8800
Levitan et al. (in prep) He I λ7065
He I λ6678
Si II λ6347?
Si II λ6371?
He I λ5876
Fe II λ5276?
Fe II λ5317?
Fe II λ5169
Fe II λ5198
0.8
0.7
0.6
0.5
4000
He I λ4471
0.1
He I λ4387
0.2
He II λ4200
0.3
He I λ4026
0.4
He I λ3888
Ca II λ3933
Ca II λ3968
4400
⊕
4800
5200
5600
6000
⊕
6400
6800
Wavelength (Å)
16
PTFS1122aw
17
Period as of yet unmeasured But not significant metal lines Magnitude
Normalized Flux
0.9
He I λ5015
He II λ4686
1.0
He I λ4921
PTFS1122aw 18
19
20
21
22
0
Levitan et al. (in prep) 20
40
60
80
HJD − 2454832.5
100
120
140
He I λ7065
He I λ6678
0.9
He I λ5876
He I λ4921
1.0
He I λ5015
PTFS1119aq 0.8
18.5
No>ce the strong He II emission 0.5
0.4
Magnitude
19.5
0.6
4000
20.5
21.0
4400
0
He II λ4686
He I λ4471
He I λ4387
He II λ4200
He I λ4026
0.1
20.0
21.5
0.3
0.2
PTFS1119aq
19.0
He I λ3888
Normalized Flux
0.7
5
10
15
20
25
30
HJD − 2454832.5
4800
5200
5600
Wavelength (Å)
6000
6400
6800
35
Summary of Results •  The PTF has discovered 6 new AM CVn systems for sure, plus 1119aq and 11dkq •  This is over 20% of the total AM CVn populaFon •  But these are also the faintest systems •  Simultaneous spectroscopic and photometric observaFons allow linking periods •  This is a systemaFc search for AM CVn systems that does not rely on colors •  AddiFonally, over new 100 CVs have been found as part of this survey Upcoming Observing Plans •  ClassificaFon spectra of >100 targets –  Currently have about 70 “bright” targets –  About 30 addiFonal faint targets below R = 20.5 •  Follow-­‐up period determinaFon –  Phase-­‐resolved spectroscopy of PTF11aab, PTF1122aw, and PTFS1119aq –  Prove link between photometric period and spectroscopic period by measuring CR Boo •  Planning on looking through Chandra-­‐PTF cross match for short period systems Outburst Recurrence Rates SynopFc surveys provide unprecedented long-­‐term light curves of AM CVn systems. What can we say about their outbursts? TesFng PopulaFon Models Previous populaFon studies have been based on limited systems dominated by SDSS-­‐discovered systems (i.e. quiescent systems). 5
3.5
5
P = 50 min SDSS 3
12
2.5
10
Number of AM CVns (tau1, standard disk)
Number of AM CVn systems (opt)
However, evoluFonary models have not been well tested and are currently assumed to be very simple. Is this actually the case? 14
x 10
x 10
82
6
1.5
4
1
2
0.5
0
0
0
0
2
4
1000
6
2000 Age
8
(years) 3000
Period (s)
10
12
4000
14
x
9
105000
6000
Nissanke et al (2012) AM CVn System Discoveries PTF SDSS AM CVn Photometric CalibraFon to SDSS Ofek et al.
1
0.1
8
0.09
4
2
0
2
4
6
8
1
14
15
•  Obtain photometric zero-­‐points for all exposures (whether in SDSS field or not) •  Find a “Zero-­‐Point VariaFon Map” to account for changes in r
[mag]
the PSF ver the chip Ofek
eto
al.
16
17
18
SDSS
19
20
21
0.08
68 percentile/2 [mag]
6
0.07
0.06
0.05
0.04
0.03
0.02
0.01
22
0
14
15
<R
16
17
> [mag]
PTF
18
19
Ofek et al (submiped) 1.— rSDSS − RPTF/SDSS as a function of SDSS r-band magnitude
F IG . 4.— R-band magnitude vs. scatter for stars in PTF field 100037
14
for point sources in a single PTF CCD image.
The image was taken
CCDID=
0. The plot shows the 68th percentile range divided by 2 as a
filter
wewas
fitcentered
the following
model:
March 18.3696 with CCDID= 0band
where the PTF
camera
function of the PTF mean magnitude (not color corrected). The 68th perfield 2961.
ion
of PTF data
centile range, for each source, is calculated over 27 images of this field taken
inst
between
March
and October
2010 which
r
(rSDSS
− iSDSS
) have photometric calibration bright−
R
=
ZP
R + !c,R
SDSS
vey
photometric
PTF
star RMS value (parameter APBSRMS in Table 2) of less than 0.04 mag. We
1
!ac,R
+ that
−atiSDSS
) end is due to saturated stars.
+!a,R AMnote
ote that the relathe AM(r
increase SDSS
in scatter
the bright
achieves accu62011; Agüeros
4011; Polishook
pipeline will be
8
2
tmRepeatability
)2
+!t,R (t − tm ) + !t2,R (t −
6.2.
−2.5 log10 (" t),
(1)
The stability over time of the PTF R-band photometric solutions
is demonstrated in Figure 4. This figure shows the
while for g-band observations
we
fit:
scatter in the calibrated magnitude of each star, over multiple
epochs, as a function of magnitude. The scatter is calculated
inst
Photometric CalibraFon to SDSS •  Obtain photometric zero-­‐points for all exposures (whether in SDSS field or not) •  Find a “Zero-­‐Point VariaFon Map” to account for changes in the PSF over the chip the field are non-variable and identifying an optimal
point for the exposure. We expanded on this to si
taneously solve for both the zero-point and additi
de-trending terms that corrected for airmass and in
ment changes. The algorithm is similar to that devel
in Honeycutt (1992) and is described in the append
Ofek et al. (2011).
To accomplish the de-trending, we modeled each
servation
as each detecFon as Model nk
�
βk cj
mi,j = M j + Zi + αcj Ai + RelaFve Photometry k=1
Merged Sources Calibrated nd opFmum i to where and the fineeded
data Zis:
Catalogs minimize scaper across •m
: the magnitude of source j on exposure i
all i,jexposures RelaFve Photometry Pipeline Source DetecFons Reference Catalogs Calibrate best exposures (systemaFcs < 1%) • cj : a color for each source. The color is requ
to compensate for the stronger effects of airm
on blue stars, as well as the the differences in C
efficiency
over a rangeCalculate of wavelengths.
For our
Fit “bad” exposures staFsFcs, �
�
�
curves,
gj −r
gjrror, and rj� ref
j , where e
using model we used cj =final systemaFc the magnitudes of the jth source
magnitudes etc.. in the respe
SDSS filters.
• Ai : the airmass of each exposure.
and the terms to be fitted are:
ES CeF PTF1J0719+4858 Analysis PTF1 J0719+4858 Orbital Period: 26.77 minutes Super-­‐outburst recurrence Fme: 65-­‐80 days 1.5
1.0
0.5
0.0
17.0
−1500
0
Line velocity (km s−1 )
PTF1J0719+4858 “S-­‐Wave” 19.32
19.36
Magnitude (g � )
P60
FTN
BOS
17.5
1500
Magnitude (g � )
Orbital Phase
2.0
19.40
18.0
18.5
19.0
19.5
20.0
19.44
1
19.48
2
3
4
HJD − 2455589.0
19.52
19.56
0.0
0.2
0.4
0.6
0.8
1.0
Phase
PTF1J0719+4858 Quiescent Variability PTF1J0719+4858 Normal Outburst 5
Eclipsing Binaries Project just starFng, but already likely results: