フェルミ衛星の現状とIceCube ニュートリノイベントの可視近赤外線フォローアップ
田中康之（広島大学宇宙科学センター）#一部のフェルミ内部資料を削除していますOutline• Introduction of Fermi/LAT• Fermi/LAT transient search in various timescales✓ LAT Transient Factory✓ LAT automated Science Processing+Flare advocate✓ Fermi All-sky Variability Analysis (FAVA)• IceCube optical/NIR follow-up by Japanese telescopes✓ Kanata/HONIR follow-up for IceCube161210✓ Future plan

Fermi Gamma-ray Space Telescope• Launched on 2008 June 11• Continue to observe without any
critical problems• All sky survey mode
Large Area Telescope (LAT)- 20 MeV-300 GeV- Thanks to the wide FoV of 2.4 str, scan all-sky every 3 hours

Gamma-ray Burst Monitor (GBM)- 8 keV-40 MeV- all-skyLarge Area Telescopeγ

Pair-conversion telescope

ACDTracker

Si-strip Tracker with tungsten foil converter:
Measure the photon directionCsI Calorimeter: Measure the photon energy,
Image the shower
ACD (Plastic scintillator):
Reject charged-particle background•••••

Large effective area (9000 cm2 @ 1 GeV,normal incidence)
Large field-of-view (2.4 str)
The entire sky is observed every ~3 hours
Energy range: 20 MeV – 300 GeV
Angular resolution (68% contaminant radius):
0.6 deg @ 1 GeV

e+ eCsI Calorimeter4 x 4 modular array
3000 kg, 650 W

Energy resolution and PSF• 12 layer (FRONT)• 4 layers (BACK)
https://www.slac.stanford.edu/exp/glast/groups/canda/lat_Performance.htm

All-sky survey-mode observation• Thanks to the large FoV of 2.4 str, LAT scans all-sky every
3 hours (i.e., 2 orbits) and perform unbiased survey

3FGL catalog from 4-year data(http://fermi.gsfc.nasa.gov/ssc/data/access/lat/4yr_catalog/)• Arxiv: 1501.02003• 3033 sources with TS>25 (~5sigma) detection• 992 sources are unID
• GeV spectra and 4-year light

curves are available for all thesources

3LAC (LAT AGN Catalog)

Ackermann+15• 467 FSRQs• 632 BL Lacs
• 460 Uncertain type• 32 non-blazar AGN

Confirmation of Blazar sequence

Fossati+98•

FSRQ: strong optical emission lines
due to bright accretion disk••

BL Lac: weak/no lines (EW<5A)
Blazar sequence: Bright/faint blazars
have lower/higher sync. peak freq.

LAT Transient Factory
GRB170214• Once LAT data is processed, automatic analysis atthe GBM trigger time is performed• The result is sent via email• Once detection with TS>25 is reported, burst

advocate run the BA tool and confirm the result• Immediately GCN draft is prepared and sent

IceCube-161210• At the IceCube trigger time, theevent position is outside LAT FoV• No LAT emission by LTF• TS maps by manual analysis foundweak sources at the edge of theIceCube error circle??

• Maybe statistical fluctuation
TSmap for T0-24h~T0

T0~T0+24h

LAT Automated Science Processing (ASP)+Flare advocate• Flare Advocate run the daily (1-day and 6-hour data) analysis script
and check the ASP result• Once transient objects are found, Astronomers Telegram is issued(typically, flux >1.0x10-6 photons/cm2/s for E>100 MeV)• LAT daily report is uploaded on
the confluence page• 24-hour, 6-hour x4

LAT information except Atel
Fermi monitored source
list light curve

Weekly Fermi sky blog

daily, weekly light curves forbright sources

Weekly digest is uploaded everyweek

Transient modulated gamma-rays from Cygnus X-3
LAT detection during giant
radio flare

High Mass
2.5x1011cm

RadioD~7 kpc
P=5.4 hour

LAT

Clear modulation
LAT
X-ray
Abdo+09

Nova is also GeV emitter
Symbiotic system
Red Giant

E>100 MeVWD
Hydrogen burningon top of WD• V407 Cyg is symbiotic nova, not classical nova (D~1 kpc)
• LAT detected high-energy gamma-rays from Nova V407 Cyg
in 2010 (Abdo+10)

LAT observation

Abdo+10• Gamma-ray emission lated for ~10 days
• Pizero decay is favored, but leptonic origin cannot be ruled out

TOO Pointed observation
3C 454.3 (Ackermann+10)

Crab nebula flare (Buehler+12)

TOO• ToO observation sometimes triggered based on interesting

phenomena such as brightest flares (3C 454.3, Crab, PSR B1259-63,
Cygnus X-3, Sun, 3C 279,,,)• Exposure increase by a factor of ~5 compared to survey mode
• Modified survey mode is also feasible (one orbit for northern sky andfollowing 2 orbits for southern sky)

PeV neutrino association with highfluence GeV blazars PKS 1424-418

Kadler+16

Fermi All sky Variability Analysis (FAVA)•Comparison of observed emission
with average emission•••

Weekly time interval•

By using 47 month Fermi/LAT data,
215 sources in the first flarecatalog

E>100 MeV, E>800 MeV
Crab nebula flare is first detectedby this analysis

Exposure ratioFAVA webpage• https://fermi.gsfc.nasa.gov/ssc/data/access/lat/FAVA/LightCurve.php• Automatic production of light curve at any locations (RA, Dec)

Crab nebula flare
LAT light curve (E>100 MeV)

Variable in high-energy
tail of synchrotron

Synchrotron

Abdo+11, Buehler+12ICGiant flare in 2011 April
Doubling timescale of ~8 hour(Compact emission region ofL<ctd~2.8x10-4 pc)
Isotropic peak luminosity is4x1036 erg/s (~1% of total spindown power)
Cutoff Energy is above 400 MeV(this is above theoretical upper
limit of cutoff energy of ~200
MeV)

Buehler+12, 田中孝+12(物理学会誌)

Summary transientof Fermi LATsearchtransient summary
searchFermi-LAT• LAT Transient Factory: Search for GeV emission at GBM trigger timefor GRB, GW trigger time, IceCube trigger time over the timescaleof <~10^4 sec• LAT ASP+Flare advocate: 6-hour and 1-day accumulated data,Galactic and extragalactic transients such as Nova and blazar flares• FAVA: 1-week accumulated data, Crab flareNo detection of LAT
counterpart for IceCube events(160427)

Outline• Introduction of Fermi/LAT• Fermi/LAT transient search in various timescales✓ LAT Transient Factory✓ LAT automated Science Processing+Flare advocate✓ Fermi All-sky Variability Analysis (FAVA)• IceCube optical/NIR follow-up by Japanese telescopes✓ Kanata/HONIR follow-up for IceCube161210✓ Future plan

Kanata/HONIR ToO observation
for IceCube-161210•••

IceCube-161210

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1.5m Kanata telescope located at Higashi-Hiroshima

2016 December 10, UT 20:06:40.31
RA=46.58, Dec=14.98, error circle radius=1 degree(50% C.L., systematic error included)

J and R-band simultaneous imaging
60 s (J) and 75 s (R) exposure in 1 frame
5-dithtering
HONIR FoV: 10’x10’
Central region of the large error circle was observedby 4x4 tiling observation (2hours for 16 pointings )J-band tiling observation
IceCube error circle(r=1.0 deg)••••

As a reference frame, we used 2MASS images (2 Micron All Sky survey) and produced
subtracted image
Check the transients by eye
No bright transient in the image, 5 sigma limiting magnitude J=18.8 (Mori et al., GCN20263)
R-band analysis is still ongoing. (Subtraction of Pan-STARRS images is not going well)Blazar candidate selected by radio catalogs••

Blazars usually show flat radio spectrum with spectral index α<-0.5 (Fν ∝να)Flat spectrum radio sources are selected from latest radio catalog✓NVSS (NRAO VLA Sky Survey) 1.4 GHz catalog (>2.5 mJy, 2 million sources, Condon+98)✓TGSS (TIER GMRT Sky Survey) 150 MHz catalog (>3.5 mJy, 0.6 million sources, Intema+16)

Kimball+08

Intema+16

Flat-spectrum radio sources
within IceCube error circle
IceCube error circle(r=1.0 deg)•••

6 flat-spectrum radio sources are found within the IceCube error circle
No CRATES source within the error circle (CRATES catalog is all-sky blazar catalog)
Only one sources within HONIR tiling observation region

Search for NIR counterpartfor flat-spectrum radio source• No bright transiet is found at the location of one flat-spectrum radio•

source (J>18.8)
Pointing observation toward CRATES sources and/or flat spectrum
radio sources would be efficient strategy for standard FoV instruments
such as Kanata/HONIRSummary• We performed Kanata/HONIR R and J-band simultaneous imaging
observation for IceCube161210• No bright transient: J>18.8 (R-band data analysis is ongoing)• Wide-field camera such as Kiso/KWFC, Kiso/Tomo-e Gozen,
Mitsume is needed• Selection of flat-spectrum radio sources by using NVSS (1.4 GHz)and TGSS (0.151 GHz) catalogs• Pointing observation toward flat spectrum radio sources would be
efficient strategy for standard FoV instruments such as Kanata/HONIR• Subaru/HSC deep observation is essential to catch IceCube
counterpart (based on the flaring blazar hypothesis)