Transient Science with Hyper Suprime-Cam · Transient Science with Hyper Suprime-Cam Masaomi Tanaka (National Astronomical Observatory of Japan) HSC transient group Nozomu Tominaga

Transient Science with Hyper Suprime-Cam

Masaomi Tanaka(National Astronomical Observatory of Japan)

HSC transient groupNozomu Tominaga (Konan U), Tomoki Morokuma (U. Tokyo),

Naoki Yasuda (U. Tokyo/Kavli IPMU), Hisanori Furusawa (NAOJ), et al.

The most famous optical transient

Supernovae

Type Ia Core-collapse

SN cosmology

M. Weiss

massive star

David A. Hardy

WD

Progenitor systems(WD+MS/RG or WD+WD)

Nucleosynthesis

Explosion mechanism

Tracer of star formation

Nucleosynthesis

•Transient surveys: Why HSC?

• Science with HSC

•Current status and initial results


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4 S. R. KULKARNI CALTECH OPTICAL OBSERVATORIES PASADENA, CALIFORNIA 91125, USA

The sources of interest to these facilities are connected to spectacular explosions. How-ever, the horizon (radius of detectability), either for reasons of optical depth (GZK cuto↵;�� ! e±) or sensitivity, is limited to the Local Universe (say, distance . 100Mpc). Un-fortunately, these facilities provide relatively poor localization. The study of explosions inthe Local Universe is thus critical for two reasons: (1) sifting through the torrent of falsepositives (because the expected rates of sources of interest is a tiny fraction of the knowntransients) and (2) improving the localization via low energy observations (which usuallymeans optical). In Figure 2 we display the phase space informed by theoretical considera-tions and speculations. Based on the history of our subject we should not be surprised tofind, say a decade from now, that we were not su�ciently imaginative.

Figure 2. Theoretical and physically plausible candidates are marked in theexplosive transient phase space. The original figure is from Rau et al. (2009).The updated figure (to show the unexplored sub-day phase space) is from theLSST Science Book (v2.0). Shock breakout is the one assured phenomenon on thesub-day timescales. Exotica include dirty fireballs, newly minted mini-blazars andorphan afterglows. With ZTF we aim to probe the sub-day phase space (see §5).

The clarity a↵orded by our singular focus – namely the exploration of the transientoptical sky – allowed us to optimize PTF for transient studies. Specifically, we undertakethe search for transients in a single band (R-band during most of the month and g bandduring the darkest period). As a result our target throughput is five times more relativeto multi-color surveys (e.g. PS-1, SkyMapper).

Given the ease with which transients (of all sorts) can be detected, in most instances, thetransient without any additional information for classification does not represent a useful,let alone a meaningful, advance. It is useful here to make the clear detection betweendetection7 and discovery.8 Thus the burden for discovery is considerable since for most

7 By which I mean that a transient has been identified with a reliable degree of certainty.8By which I mean that the astronomer has a useful idea of the nature of the transient. At the very

minimum we should know if the source is Galactic or extra-galactic. At the next level, it would be useful

LSST Science Book (after Rau+09, Kasliwal+,Kulkarni+)

Nova

Supernovae

Depth

Area

CadenceOptical Transient

Search





Supernova science with HSC

SN cosmology=> up to z~1.5!

Progenitor systems delay time

metallicity dependence (z > 1)

Tracer of star formationbest SN rate up to z ~1

Type Ia Core-collapse

M. Weiss

massive star

David A. Hardy

WD

“Superluminous” supernovae

(e.g., Quimby+11, Gal-Yam+12, Cooke+12, Smartt 12)

L ~ 1010 Lsun ~ 10 x L(Type Ia SN)- huge amount of radioactive 56Ni- kinetic energy => radiation energy

“Superluminous” supernovae at z ~ 5-6Detectability of High-Redshift Superluminous Supernovae - II. Beyond z=6 11

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Hummel J. A., Pawlik A. H., Milosavljevic M., Bromm V.,2012, ApJ, 755, 72

Ishida E. E. O., de Souza R. S., Ferrara A., 2011, MNRAS,418, 500

Ivezic Z. et al., 2008, arXiv:0805.2366Johnson J. L., Dalla V. C., Khochfar S., 2013, MNRAS,428, 1857

Kasen D., Bildsten L., 2010, ApJ, 717, 245Kasen D., Woosley S. E., Heger A., 2011, ApJ, 734, 102Kawabata K. S., Tanaka M., Maeda K., Hattori T., NomotoK., Tominaga N., Yamanaka M., 2009, ApJ, 697, 747

Laureijs R. et al., 2011, arXiv:1110.3193LSST Science Collaborations et al., 2009, arXiv:0912.0201Mesinger A., Johnson B. D., Haiman Z., 2006, ApJ, 637,80

Miller A. A. et al., 2009, ApJ, 690, 1303Miralda-Escude J., Rees M. J., 1997, ApJ, 478, L57+Miyazaki S. et al., 2006, in Society of Photo-Optical In-strumentation Engineers (SPIE) Conference Series, Vol.6269, Society of Photo-Optical Instrumentation Engineers(SPIE) Conference Series

Moriya T., Tominaga N., Tanaka M., Maeda K., NomotoK., 2010, ApJ, 717, L83

Moriya T. J., Blinnikov S. I., Tominaga N., Yoshida N.,Tanaka M., Maeda K., Nomoto K., 2013, MNRAS, 428,1020

Moriya T. J., Tominaga N., 2012, ApJ, 747, 118Neill J. D. et al., 2011, ApJ, 727, 15Nugent P., Kim A., Perlmutter S., 2002, PASP, 114, 803Ofek E. O. et al., 2007, ApJ, 659, L13Oguri M., Marshall P. J., 2010, MNRAS, 405, 2579O’Shea B. W., Norman M. L., 2007, ApJ, 654, 66Pan T., Kasen D., Loeb A., 2012, MNRAS, 422, 2701Pan T., Loeb A., Kasen D., 2012, MNRAS, 423, 2203Quimby R. M., Aldering G., Wheeler J. C., Hoflich P., Ak-erlof C. W., Rykoff E. S., 2007, ApJ, 668, L99

Quimby R. M. et al., 2011, Nature, 474, 487Quimby R. M., Yuan F., Akerlof C., Wheeler J. C., 2013,MNRAS

Ren J., Christlieb N., Zhao G., 2012, Research in Astron-omy and Astrophysics, 12, 1637

Robertson B. E., Ellis R. S., 2012, ApJ, 744, 95Rydberg C.-E., Zackrisson E., Lundqvist P., Scott P., 2013,MNRAS, 429, 3658

Scannapieco E., Madau P., Woosley S., Heger A., FerraraA., 2005, ApJ, 633, 1031

Smith N. et al., 2008, ApJ, 686, 485—, 2007, ApJ, 666, 1116Stacy A., Greif T. H., Bromm V., 2010, MNRAS, 403, 45Takahashi R., Oguri M., Sato M., Hamana T., 2011, ApJ,742, 15

Tanaka M., Moriya T. J., Yoshida N., Nomoto K., 2012,MNRAS, 422, 2675

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LSSTLSST deep drillingHSC DeepHSC UltraDeep

Figure A2. Expected number of SN detection per dz = 0.5 binas a function of redshift with LSST surveys. For the adoptedsurvey parameters, see Table A1. For comparison, we show thesimulations with the HSC survey strategy (Deep and UltraDeeplayers). In this figure, a constant limiting magnitude in opticalwavelengths is assume for simplicity. See Paper I for more detailedsimulations with HSC. All the simulations have been performedfor Case B SFR density and Model 08es.

Whalen D. J. et al., 2012, arXiv:1211.4979—, 2013a, ApJ, 768, 195Whalen D. J., Fryer C. L., Holz D. E., Heger A., WoosleyS. E., Stiavelli M., Even W., Frey L. H., 2013b, ApJ, 762,L6

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Yamada T. et al., 2012, in Society of Photo-Optical In-strumentation Engineers (SPIE) Conference Series, Vol.8442, Society of Photo-Optical Instrumentation Engineers(SPIE) Conference Series

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Yoshida N., Omukai K., Hernquist L., 2007, ApJ, 667, L117Young D. R. et al., 2010, A&A, 512, A70+Zheng W. et al., 2012, Nature, 489, 406

APPENDIX A: APPLICATION TO UPCOMING

OPTICAL SURVEYS

We also apply our simulations to upcoming optical sur-veys. Paper I performed detailed simulations with realistic,planned observational strategy for Subaru Hyper Suprime-Cam (HSC, Miyazaki et al. 2006) survey. On the other hand,as shown in Section 5, it is useful to study a wide range ofparameters to find the optimized survey strategy. In thissection, we present simpler simulations for optical surveys,but with a wider parameter space.

With optical surveys, detection of SLSNe up to z ∼ 5 is

c⃝ — RAS, MNRAS 000, 1 - ??

MT+13

3 deg230 deg2

100 deg220000 deg2

Deep transient survey with Subaru/HSC

Detectability of High-Redshift Superluminous Supernovae - II. Beyond z=6 9

Table 1. Parameters for upcoming NIR surveys

Survey Area Depth Wavelength range Cadence Duration(deg2) (mag)

Optimal (z > 10) 100 26.0 3-5µm 3 months 3 yearsOptimal (z > 15) 200 26.0 3-5µm 3 months 3 years

Euclid 40 24.5 (visual), 24.0(Y, J, K) 0.55 - 2 µm (visual - H) 10 days 3 yearsWFIRST 6.5 26.0 0.73 - 2.4 µm (Z - K) 5 days 1.8 years

WFIRST-extended 100 26.0 0.73 - 2.4 µm (Z - K) 5 days 1.8 yearsWFIRST-extended +3µm 100 26.0 0.73 - 3.0 µm 5 days 1.8 years

WISH 100 26.0 1.0 - 4.5 µm 10 days 1 year

∗ Limiting magnitude per visit, but it can also be the limiting magnitude in the stacked image for a given period within the cadence.

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Figure 11. Expected number of SN detection per dz = 0.5 binas a function of redshift with upcoming NIR surveys. For theadopted survey parameters, see Table 1. WFIRST (black andblue lines) covers the wavelength range up to K-band (2.4 µm).If a 3 µm-band is hypothetically added, the highest redshift willexceed z = 10 (pink line). Since WISH plans to cover up to 4µm,SNe at higher redshifts can be detected. All the simulations havebeen performed for Case A SFR density and Model 08es.

mag in the visual band and 24.0 mag in the NIR bands. Wehypothetically assume 10-day cadence and 3-year survey pe-riod. We perform mock observations with these parameters.Throughout this section, we adopt Case A SFR density andModel 08es. The result is shown in the gray line in Figure11. Euclid will be able to discover ∼ 1000 SLSNe at z < 5.The maximum reachable redshift is about z = 5, which islimited by the 24.0 mag depth at 2 µm (see Figure 2).

Euclid will provide an unprecedented sample of SLSNe.Since about half of SLSNe detected by Euclid are located atz < 2, they can also be observed with optical spectroscopy(Cooke et al. 2009, 2012). With this sample, we can studystatistical properties of each class of SLSNe (SLSN-I andSLSN-II, see Quimby et al. 2011; Gal-Yam 2012), such as theluminosity function and statistics of the light curve duration,which can be used to unveil the nature and progenitors ofSLSNe.

Next, we consider surveys with WFIRST. WFIRSTplans to perform dedicated SN survey in a part of the ob-servational time (Green et al. 2012). The planned survey

area is 6.5 deg2 (wide) and 1.8 deg2 (deep). Since a largesurvey area is critical for the detection of SLSNe (Figure8), we adopt 6.5 deg2. The wavelength coverage is up to 2.4µm (K-band) and the survey depth per visit is 26.0 mag.Cadence and survey period are 5 days and 1.8 years, respec-tively, which are optimized for Type Ia SNe. The result ofmock observation with these parameters (WFIRST, Table1) is shown in black line in Figure 11. Thanks to the deepobservations at 2.4 µm, WFIRST will be able to discover∼ 400 SLSNe up to z ∼ 7.

It is also shown, however, that the survey area of 6.5deg2 is not enough to fully utilize its observational depth.To see this effect, we hypothetically perform the simulationswith the survey area of 100 deg2 with all the other param-eters kept the same (WFIRST-extended, Table 1). Such asurvey dramatically increases the number of SLSNe (see Fig-ure 8): ∼ 6000 SLSNe up to z ∼ 9 will be detected (blueline in Figure 11).

Even with the extended survey area, there is a clearcutoff in the expected number of SLSNe below z ∼ 10.This is because the expected brightness of SLSNe in theK-band (1.8-2.4 µm) becomes dramatically fainter at theredshifts higher than z ∼ 5 (Figure 2). To see the advantageto have 3µm band, we perform a simulation by hypothet-ically adding 3µm band to the WFIRST-extended survey(pink line in Figure 11). If WFIRST possibly covers 3µm, itwill be able to carry out the nearly ideal survey, detectingSLSNe at z > 10. We emphasize the importance of observa-tions at ≥ 3 µm.

WISH plans to focus on the deep survey with ∼ 100deg2 (Yamada et al. 2012). The wavelength range is 1.0-4.5µm and the survey depth per visit is about 26.0 mag. Ca-dence and survey period are not yet fixed, and thus, we hypo-thetically assume 10-day cadence and 1-year survey period(see WISH in Table 1). The brown line in Figure 11 showsthe expected number of SLSNe with WISH survey. WISHwill be able to detect about 3000 SLSNe in total. Thanks tothe wavelength coverage up to 4.5 µm, the maximum red-shift is higher than those of Euclid and WFIRST. It may beable to discover SLSNe up to z ∼ 12. This is, in fact, quitesimilar to the optimized survey strategy to detect SLSNe atz > 10 suggested in Section 5.

WISH and extended WFIRST surveys will be able todetect more than 100 SLSNe at z > 6 (see also Figure 8).Such high-redshift SLSNe can be spectroscopically observedwith JWST and also ground-based 30m-class telescopes,

c⃝ — RAS, MNRAS 000, 1 - ??

Excellent prior for future NIR surveys

Toward “first” supernova!(Unique probe for single Pop III star)

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Synergy with X-ray observations

By T. Moriya

Superluminous supernovaL (opt) ~ 1044 erg s-1

E (opt) ~ 1051 erg

- huge amount of radioactive 56Ni- kinetic energy => radiation energy

X-ray detection from SLSN at z ~ 1The Astrophysical Journal, 771:136 (10pp), 2013 July 10 Levan et al.

Figure 1. Soft band images of SCP 06F6, obtained from XMM-Newton observations in the MOS1 (left), MOS2 (middle), and pn (right) detectors (MOS1 and MOS in0.2–2 keV, and pn in 0.3–1 keV). Each image is approximately 2 arcmin across. The source is clearly visible in MOS1 and MOS2, and detected at ∼3.0σ confidencein the pn. The red crosses show the optical position of SCP 06F6 from Barbary et al. (2009), while the blue crosses show the positions derived for the X-ray sourcevia the standard detection algorithms.(A color version of this figure is available in the online journal.)

Quimby et al. 2011c). In addition, a population of SNe showingclear exponential tails due to nickel production (SLSN-R) mayrepresent the best candidates to be PISN-like events (e.g.,Gal-Yam et al. 2009; Gal-Yam 2012).

To date, the majority of diagnostics of the nature of theseexceptionally luminous SNe have unsurprisingly focused onlonger wavelength regimes, since this is where their luminosi-ties seem to peak. Here we consider an alternative approach ofutilizing the insights that can be gained from sensitive X-rayobservations to distinguish between plausible models. Wepresent a thorough re-analysis of X-ray observations of the firstidentified SLSN-I, SCP 06F6, confirming it to be a luminousX-ray emitter at late times after the initial identification of theoutburst, if this X-ray emitting phase was at all extended thenthe X-ray energy output could rival or exceed that seen in theoptical. We additionally show that limits for other SLSNe-I ob-served in the X-ray band, imply that such X-ray emission is rare(<10% of SLSNe-I), and consider models that can account forsuch rare, but luminous X-ray emission.

2. X-RAYS FROM SCP 06F6

SCP 06F6 marks a prototype of the SLSN-I events, althoughthe properties of this event were sufficiently unusual that itinitially defied classification (Barbary et al. 2009; Gansicke et al.2009; Soker et al. 2010). Eventually, through the discovery ofother similar events, it was recognized as a highly luminousSN at z = 1.189, with a peak magnitude brighter than MV =−22 (Quimby et al. 2011c). Perhaps even more remarkablewas the detection of SCP 06F6 in X-rays with XMM-Newtonapproximately 150 days after its first discovery (Gansicke et al.2009). While this work utilized an incorrect redshift estimatefor SCP 06F6 before its more accurate identification, it alreadyimplied a high luminosity event. Corrected for the now knownredshift, the X-ray luminosity becomes even more extreme,exceeding LX ∼ 1045 erg s−1.

The XMM-Newton observations were obtained on 2006August 2, 162 days after the initial detection of the SCP 06F6outburst, and significantly after the optical peak. A total of9916 and 8220 s of good exposure were obtained with MOS1and MOS2 respectively and 2622 ks with the EPIC pn (asmaller total integration due to the longer setup time, and greater

sensitivity to background flaring). The MOS1 observations wereobtained with the medium filter in place as a safeguard againstany optical loading of CCD by stars in the field (although thesource is well out of the Galactic plane, and has only one starbrighter than R ∼ 12 in the EPIC field of view, offset severalarcminutes from the position of SCP 06F6). The MOS2 and pnobservations were obtained with the thin filter.

The XMM-Newton observations were significantly impactedby background flaring. Because of this we chose to restrict theenergy band considered to the 0.2–2 keV range and the extractedMOS images are shown in Figure 1. Within these images weperformed source detection utilizing the standard XMM-NewtonSAS tools (version 11.0.0). In both the MOS1 and MOS2 imagesthis returns a clear source, with count rates of (6.5 ± 1.4)×10−3

and (9.3 ± 1.7) × 10−3 counts s−1 respectively. The signal tonoise ratio of these detections is 4.7 and 5.3, while the reporteddetection likelihoods for each source (DET_ML) are 18.7 and24.3, corresponding to false positive probabilities of 8 × 10−9

and 3 × 10−11. In other words, these detections are highlysignificant in each detector, especially given the narrow spatialwindow searched (i.e., the false positive probabilities are closeto those above, since we have a single trial).

The pn detectors are significantly noisier, due to the shortertotal exposure and greater sensitivity to background flar-ing. Nonetheless, there is significant excess flux at the po-sition of SCP 06F6, with a measured rate of 0.0111 ±0.0037 counts s−1 (0.3–1 keV; see Figure 1). For the source inthe pn, DET_ML = 5.96, corresponding to a false positive prob-ability of 0.0025 (i.e., the source is detected at >3σ ). Since theoptical paths for each of the detectors are different this suggeststhat we have three independent detections of X-ray emissionfrom SCP 06F6.

The positions of the sources in the MOS1 and MOS2 imagesare R.A. = 14h32m28.s18, decl. = 33d32′22.′′8 and R.A. =14h32m27.s22, decl. = 33d32′22.′′9, with reported centroid errorsof ∼3 arcsec on each position (with an additional systematic of1′′–2′′, each at the 1σ level). These positions are offset ∼10′′ and∼2′′ respectively from the position of the optical source reportedby Barbary et al. (2009). Although these errors are relativelylarge, the faintness of the source and extended structure inthe high background make precise centroiding difficult. Wenote that a second X-ray source at R.A. = 14h32m46.s20

2

Levan+13

XMM-Newton(0.2-2 keV)

f (X-ray) ~ 1 x 10-13 erg s-1 cm-2

(~1 x 10-4 ph s-1 cm-2 @ 1keV)

=> L (X-ray) ~ 1045 erg s-1

4 S. R. KULKARNI CALTECH OPTICAL OBSERVATORIES PASADENA, CALIFORNIA 91125, USA

The sources of interest to these facilities are connected to spectacular explosions. How-ever, the horizon (radius of detectability), either for reasons of optical depth (GZK cuto↵;�� ! e±) or sensitivity, is limited to the Local Universe (say, distance . 100Mpc). Un-fortunately, these facilities provide relatively poor localization. The study of explosions inthe Local Universe is thus critical for two reasons: (1) sifting through the torrent of falsepositives (because the expected rates of sources of interest is a tiny fraction of the knowntransients) and (2) improving the localization via low energy observations (which usuallymeans optical). In Figure 2 we display the phase space informed by theoretical considera-tions and speculations. Based on the history of our subject we should not be surprised tofind, say a decade from now, that we were not su�ciently imaginative.

Figure 2. Theoretical and physically plausible candidates are marked in theexplosive transient phase space. The original figure is from Rau et al. (2009).The updated figure (to show the unexplored sub-day phase space) is from theLSST Science Book (v2.0). Shock breakout is the one assured phenomenon on thesub-day timescales. Exotica include dirty fireballs, newly minted mini-blazars andorphan afterglows. With ZTF we aim to probe the sub-day phase space (see §5).

The clarity a↵orded by our singular focus – namely the exploration of the transientoptical sky – allowed us to optimize PTF for transient studies. Specifically, we undertakethe search for transients in a single band (R-band during most of the month and g bandduring the darkest period). As a result our target throughput is five times more relativeto multi-color surveys (e.g. PS-1, SkyMapper).

Given the ease with which transients (of all sorts) can be detected, in most instances, thetransient without any additional information for classification does not represent a useful,let alone a meaningful, advance. It is useful here to make the clear detection betweendetection7 and discovery.8 Thus the burden for discovery is considerable since for most

7 By which I mean that a transient has been identified with a reliable degree of certainty.8By which I mean that the astronomer has a useful idea of the nature of the transient. At the very

minimum we should know if the source is Galactic or extra-galactic. At the next level, it would be useful

LSST Science Book (after Rau+09, Kasliwal+,Kulkarni+)

Nova

SupernovaeSN shock breakout

Shock breakout = the first moment of SN explosion

L12 TOMINAGA ET AL. Vol. 705

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Figure 2. Comparison between the NUV (top) and FUV (bottom) observations(points, SNLS-04D2dc; Schawinski et al. 2008) and the SN IIP model withoutthe host galaxy extinction (dot-dashed line) and reddened for the host galaxyextinction with EB−V,host = 0.06 mag (dashed line), 0.14 mag (solid line), and0.22 mag (dotted line).

the values are slightly different from Schawinski et al. (2008),the total extinction integrated over each band depends on theintrinsic spectrum and varies with time as the spectrum changes.The variations of extinction in the UV bands are relatively large;for example, ∼0.3 mag in the FUV band and ∼0.1 mag in theNUV band from t = 0 to 20 days for the SN IIP model withMZAMS = 20 M⊙ and E = 1.2 × 1051 erg.

Because of the large uncertainty, we assume several valuesfor the color excess of the host galaxy as follows: EB−V,host =0 mag referring to the case of no extinction in the hostgalaxy, EB−V,host = 0.06 mag giving half of the standardextinction in the NUV band, EB−V,host = 0.14 mag being thestandard extinction, and EB−V,host = 0.22 mag giving doubleof the standard extinction in the NUV band, which lead to(ANUV, AFUV) = (0.18 mag, 0.15 mag), (0.75 mag, 1.10 mag),(1.51 mag, 2.38 mag), and (2.27 mag, 3.65 mag), respectively.Here, we assume the SMC reddening law for the host galaxy.

Figure 2 shows comparisons of UV LCs with the model withMZAMS = 20 M⊙ and E = 1.2 × 1051 erg. The model LCs areconsistent with the observations within the uncertainty, whilethey are slightly fainter than the observations for EB−V,host =0.14 mag. The explosion energy of SNLS-04D2dc is consistentwith the canonical value of the explosion energies of core-collapse SNe (e.g., SN 1987A: E = (1.1 ± 0.3) × 1051 erg;Blinnikov et al. 2000). Although the 56Ni–56Co radioactivedecay does not contribute to the shock breakout, we expedientlyassume a canonical 56Ni ejection without mixing to the envelope(the ejected 56Ni mass M(56Ni) = 0.07 M⊙; e.g., SN 1987A:Blinnikov et al. 2000), and thus Mej = 16.9 M⊙ to yield0.07 M⊙ of 56Ni.

The second peak in the NUV LC at t ∼ 3 days is reproducedby the model and explained by the shift of the peak wavelength

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as Schawinski et al. (2008) and Gezari et al. (2008) suggested.The bolometric LC and the evolution of color temperature areshown in Figure 3. Figure 3 also shows the velocity evolutionof photosphere defined as a position where the radiation andgas are decoupled. Although the bolometric luminosity declinesmonotonically after the shock breakout, the radiation energy inthe NUV band increases with time because the peak wavelengthshifts long (Figure 1). After the NUV second peak, the color tem-perature decreases further and the peak wavelength shifts to theoptical bands. The shift is caused by not only the decreasing tem-perature of the SN ejecta, but also an enhancement of the metalabsorption lines due to the low temperature. As a result, the UVluminosity declines monotonically after the NUV second peak.The model also predicts a second peak in the FUV band but thebrightening is obscured because of the low signal-to-noise ratio.

3.2. Optical Light Curves at Plateau Stage

Thanks to the multigroup radiation hydrodynamics calcula-tions, subsequent evolutions of multicolor lights are obtainedand compared with the SNLS optical observations. Figure 4shows comparisons of the g-, r-, i-, and z-band LCs. Here, weadopt EB−V,host = 0.14 mag and the SMC reddening law forthe host galaxy. The total extinction at the effective wavelengthsof the g-, r-, i-, and z-band filters of the MegaPrime/MegaCamon CFHT are as large as Ag = 0.64 mag, Ar = 0.47 mag,Ai = 0.36 mag, and Az = 0.28 mag, respectively.

As SED peaks in the g-band at t ∼ 20 days (Figure 1),the g-band LC peaks at t ∼ 20 days. After this epoch, the


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Figure 7.6: (Left): Comparison between the GALEX and SNLS observations (points, SNLS-04D2dc,Schawinski et al. 2008) and a SN IIP model with Mms = 20M⊙ and E = 1.2 × 1051 erg reddened for the hostgalaxy extinction with a color excess E(B − V ) = 0.14 mag (lines, Tominaga et al. 2009) (black and red: near UV,green: g-band, blue: r-band, magenta: i-band). The inset enlarges the phase when the SN emitted UV light. (Right):Apparent g′-band light curve of a shock breakout in AB magnitude system for a SN IIP model with Mms = 40M⊙

and E = 1051 erg. Limiting magnitudes for a 4σ detection in 3.3 min, 5 min, 10 min, and 20 min integrations arealso shown (dashed line), assuming 0.7” seeing, 1.6 arcsec aperture, and 3 days from New Moon.

identify the shock breakout with the blue g′ − r′ color as described below. Aims of this surveyare (1) detecting numerous high-z shock breakouts and obtaining their multicolor light curves, (2)observationally establishing the physics of shock breakouts and confirming that the shock breakoutstake place universally, (3) deriving a cosmic star formation history (CSFH) up to z ∼ 1.5 with theshock breakouts, and ultimately (4) developing the totally-new high-z study with shock breakouts.

Introduction

Core-collapse supernovae (CCSNe) have been so far observed only at z ! 0.9 (Dahlen et al. 2004;Poznanski et al. 2007), except for extraordinary events like Type IIn SNe (SNe IIn) (Cooke et al.2009) and gamma-ray bursts (GRBs; Salvaterra et al. 2009). The record will be broken by a shockbreakout. The shock breakout is the bolometrically-brightest phenomenon in SNe (> 1044 ergs s−1)lasting several seconds to several hours and emits dominantly in X-ray or ultraviolet (UV) with aquasi-blackbody spectrum (T > 105 K, Blinnikov et al. 2000). Although the shock breakouts areproposed to be a probe of the distant universe, its short duration and X-ray/UV-peaked spectramake it difficult to be observed. The first and currently last complete light curve of shock breakoutof normal CCSN was obtained for SN IIP SNLS-04D2dc (redshift z = 0.19, e.g. Schawinski et al.2008) by the GALEX satellite but the detection significance in near UV and far UV bands is only! 4σ and ! 2σ, respectively.

We adopted a multi-group radiation hydrodynamics code STELLA (Blinnikov et al. 2000) andpresented X-ray-to-infrared light curves (LCs), including the shock breakout, plateau, and tail, of

13

1 day !

Figure from N. Tominaga

- Probe of high-z Universe (up to z~2)- Memory of stellar radius

High cadence

ROTSE

HST

HSC

SNLSPan-STARRS

SDSS

PTFPTF

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PTF 1m

KISS 1m

HSC!!

GRB

More“Orphan GRB”

C:ESO

Relativisticjet

e.g., Totani & Panaitescu 02, Nakar+02

GRB without gamma-ray detection

~10 detections with Deep layer of SSP





HSC pipelineImage

transient pipeline - Image subtraction- Source detection in subtracted image (> 1,000 candidates per image)- Candidate screening- ...

Realtime transient detection!=> immediate follow-up observations

Challenge: data reduction

~ 5GB

New image Reference image Subtracted image

- --

Open-use observations (2-3 Jul 2014)

Tominaga et al.

Ref New Sub

http://tpweb2.phys.konan-u.ac.jp/~tominaga/HSC-SN/

Ref New Sub



•Transient surveys• (1) Depth (2) Width (3) Cadence

•Transient science with HSC• Deep/Wide => Type Ia SNe and CC SNe

• Deep/Wide => “Superluminous” SNe at z~5-6

• High cadence => Shock breakout of SNe

• Deep/Wide => Orphan GRB

•Current status• High-cadence pilot survey in open-use time

• Realtime data reduction

• SSP data are coming

Summary

Stay tuned!!

Documents

Transient Science with Hyper Suprime-Cam · Transient Science with Hyper Suprime-Cam Masaomi Tanaka (National Astronomical Observatory of Japan) HSC transient group Nozomu Tominaga