Current progress in ESTEMA and relevant EAVN...
Transcript of Current progress in ESTEMA and relevant EAVN...
Current progress in ESTEMA and relevant EAVN commissioning
Hiroshi Imai(Center for General Education/ Amanogawa Galaxy Astronomy Research Center,
Kagoshima University)On behalf of EAVN Evolved Stars SWG and ESTEMA team
Current members• EAVN Evolved Stars SWG
Hiroshi Imai, Se-Hyung Cho, Bo Zhang (co-chair), Youngjoo Yun, Dong-Hwan Yoon, Jaeheon Kim, Haneul Yang, D.-J. Kim, Lang Cui, J. Zhou, G. Wu, Gabor Orosz, Miyako Oyadomari, Akiharu Nakagawa, Ross Burns, Richard Dodson, Maria Rioja, James Chibueze Okwe, Yuanwei, Wu, Shuangjin Xu, Tomoaki Oyama, Yoshiaki Asaki, Naoko Matsumoto
• ESTEMA (EAVN Synthesis of Stellar Maser Animations)Hiroshi Imai, Youngjoo Yun, Bo Zhang (co-P.I.) , Se-Hyung Cho, Dong-Hwan Yoon, Jaeheon Kim, Haneul Yang, Dong-Jin Kim, Lang Cui, Jianjun Zhou, Gang Wu, Gabor Orosz, Miyako Oyadomari, Akiharu Nakagawa, Ross Burns, Richard Dodson, Maria Rioja, James Chibueze Okwe, Shuangjin Xu, Tomoaki Oyama, Yoshiaki Asaki, Jun-ichi Nakashima, Andrey M. Sobolev
Our goalsvisualization of dynamic stellar mass loss
SiO masers around TX Cam (Gonidakis et al. 2013)
Distance from star (stellar radius)
Shock waves in C-rich envelope (Höfner et al. 1995)
H2O maserregion
SiO maserregion
with shock waves
without shock waves
See alsoP24 (poster) by Se-Hyung ChoNext talk by YoungJoo Yun
How are materials on the stellar surface lifted up outward in a circumstellar envelope?
Anthares In CO line center(2.31 μm) (Ohnaka et al. 2017)
Höfner (2011)
Under periodic stellar pulsationand inhomogeneous mass ejection
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Tenvelope = T*
R
R*
−2 / 5
T* ≈ 3000 K, R* ≈1-10 AU
Line overlapexcitation by Mid-IR H2O radiation
SiO maserlines(J→J-1,J=1,2,3,…;ν≈43×J[GHz])
How to collocate these maser line regions throughout stellar pulsation cycles?
Our challenges 1: simultaneous mapping of SiO maser transitions with H2O masers
Are we really watching true physical gas motions in these maser lines?
Quasi-optics for multi-band simultaneous observations
Yebes, ATCA (multi-antennas), NARIT(?), Effelsberg(?),...
Opened (2019)
In commissioning
VERAIn K/Q-bands
Commissioning of K/Q-band quasi-optics in VERA
Gain loss less than 10%(<uncertainty)by 20” beam offset(in Ishigakijima)
r19052b(W Hya and VX Sgr)
r19052a (S Per)
H2O masers
SiO masers
Source-frequencyphase-referencingtechnique should betested.
Yonsei
Ulsan
Tamna
Mizusawa
IrikiOgasawara
Ishigakijia
W Hya VX Sgr
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ESTEMA session (2 days x 4 hours/day)
• KaVA/EAVN: mapping H2O and SiO (43 GHz) masers à should be made in one day in future• KVN: band-to-band phase transfer calibration for SiO masers (43/86/129 GHz)• VERA: dual-beam astrometry and wide-band recording (for SiO v=3 and v=0 J=1à0 masers)
Our challenges 2: operating “hybrid” modeThree vex files for one-day block
Target sources of ESTEMA
Targeting biweekly (~20 sessions per year) snapshot (<4 hours with > 5 telescopes)
15 d15 d20 d20 d30 d60 d
Cadence
IRC-10151
Our challenges 3: time allocation with high cadence
15 d15 d20 d20 d30 d60 d
Cadence
IRC-10151
Negotiation in time allocation
Requesting ~550 hours/yr, ~2600 hours in totallAvoiding condensed LST zone (16—22 hours)lReducing to ~ 65% with K/Q-band simultaneous observations with VERAlReducing to ~ 50% by adding more telescopes (Nb, T6, Ur, Tl)
VLBI mapping of 16 circumstellar H2O maser sources - persistent clumps but changed distribution biases -
With full JVN(VERA+NRO+Takahagi+Tsukuba+Kashima(Imai et al. in preparation)
Contour peak: 120.5 Jy beam-1 km s-1
20 mas
S Per
Contour peak: 22.6 Jy beam-1 km s-1
20 mas
AP Lyn
50 mas
VY CMa
Contour peak: 129.6 Jy beam-1 km s-1
20 mas
R Crt
Contour peak: 871.8 Jy beam-1 km s-1
Contour peak: 43.9 Jy beam-1 km s-1R.A. offset
Contour peak: 103.6 Jy beam-1 km s-1R.A. offset
20 mas
RT VirS Crt
10 mas
Decl.
offs
etDe
cl. o
ffset
Decl.
offs
et
Decl.
offs
et
Contour peak: 86.4 Jy beam-1 km s-1
20 mas
IRC-10414
Contour peak: 5.2 Jy beam-1 km s-1
50 mas
W Hya
10 mas
RX Boo
Contour peak: 5.4 Jy beam-1 km s-1
Decl.
offs
et
50 mas
S CrB
Contour peak: 6.9 Jy beam-1 km s-1
20 mas
U Her
Contour peak: 27.0 Jy beam-1 km s-1
50 mas
VX Sgr
Contour peak: 437.3 Jy beam-1 km s-1R.A. offset R.A. offset
Decl.
offs
et
Decl.
offs
et
Contour peak: 420.3 Jy beam-1 km s-1
10 mas
R Aql
20 mas
RR Aql
Contour peak: 3.0 Jy beam-1 km s-1
Decl.
offs
et
Contour peak: 240.4 Jy beam-1 km s-1
20 mas
NML Cyg
20 mas
R Cas
Contour peak: 2.1 Jy beam-1 km s-1R.A. offset R.A. offset
Indicating importance of long-term monitoring of circumstellar H2O masers
TimevariationoftotalH2OmaserfluxtowardWHydrae(Shintani etal.2008)
What determines the extent and bias in H2O maser distribution?
DistributionextentofcompactH2OmasersaroundWHydrae(Imai,Nakagawa&Takaba 2019)
What determines the extent and bias in H2O maser distribution?
Phase lag of total H2O flux(Shintani et al. 2008)
Our decadal effortsØCommissioning works in KaVA/EAVN Evolved Stars SWG
üSince 2011 May üDemonstration of KaVA full-track / snap-shot imagingüDevelopment of scheme of hybrid observation modes
ØKaVA ESTEMA (Expanded Study on Stellar Masers)ü2015 November—2017 MarchüSnapshot imaging of ~40 stellar maser sources successfully detected
ØESTEMA (EAVN Synthesis of Stellar Maser Animations)üFrom 2018 MayüTargeting 6 stars (currently 2 stars) with different stellar pulsation
periods
S PerIn direct band-to-band
phase-transfer(Asaki et al. in prep.)
First KQW-band composite map of H2O and SiO masers
H2O (surviving over a decade)SiO v=1 J=1à0SiO v=2 J=1à0SiO v=1 J=2à1
Confidential
First KQW-band composite map of H2O and SiO masersS Per(Asaki et al. in prep.)
Ø Good assumption of maser distribution corresponding to true gas distribution
Ø Double SiOmaser rings
Ø Radial correlationamong H2O and SiO masers
Ø Episodicmass ejectionevery decade
Confidential
Venn diagram of VLBI fringe detections of KaVA ESTEMA circumstellar maser sources
H2O42
In scalar averaging
SiO J=1à0 54(v=2) 51(v=1)
9
16 SiOJ=2à1 27
152
SiO J=3à25
37
11
Image cube synthesis and statistical inspection still ongoing
80 stars in total(2015̶2017)
Ring (circle)-model fittingØKVN-KSP method using maser spot/feature maps
üInformation of maser emission distribution reduced to representative brightest peaks in the spots/features
ØEHT method finding azimuthal offset brightness peak üAvailable to a maser ring extremely biased, clumpy, and complicated?
ØESTEMA method finding the sharpest radial profile1.Determining the ring center at first using data of
a distribution of maser emission areas2.Estimating the ring size and widthChallenging to ring size accuracy better than 0.5 masExtension to ellipse fitting àfor masers around red supergiants
ESTEMA method
Demonstrated by Miyako Oyadomari
r18145a1 ch à 0.1 mas
D1 (5%̶95%)
D2 (5%̶50%)
Finding the minimum
Defined ring radius
Cum
ulat
ive
norm
alize
d flu
x
Demonstrated by Miyako Oyadomari
ESTEMA method r18145a1 ch à 0.1 mas
In 1000 trials in a Monte-Carlo simulation
Number of trials
Difference in the performances between SiO v=1 and v=2 J=1à0 maser lines
Preliminary
by Miyako Oyadomari
How to track true physical gas motions on sub-mass scale ?
See also talks byAkiharu Nakagawa(this session) and Haneul Yang and Shuangjing Xu (Astrometry session)
Very long time-domain astronomy with image cubes
FLASHING early science (Imai et al. 2020 PASJ Special Issue, submitted)-160 -80 0 80 160 240
LSR velocity [km/s]
0
1
00
2
00
3
00
4
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0 -100
Decl.
offs
et (m
as)
R.A. offset (mas)
+
200 AUat 3.6 kpc
2006 Sep.ー2007 Feb.2009 May2019 March
New bipolar bulletejections
l Weekly̶monthly maser flaresl Decadal evolutionl Permanent turn off of a jet to become a planetary nebula
IRAS 18286-0959(water fountain from
a dying star)
Summary and future perspectivesØCommissioning to deliver the full set of circumstellar H2O and SiO
maser animationsH2O, SiO (v=0, 1, 2, 3, J=1à0 / v=1 J=2à1, J=3à2 / 29SiO v=0, J=1à0)Toward synchronized operation of VERA (K/Q) and Nobeyama
(K/Q/W) with KaVA/EAVN/ and the Global AllianceØKaVA ESTEMA: statistical analyses based on snap-shot image
cubes from ~20 starsüAstrometric registration ongoing üComparisons with latest data: Gaia DR2, VLTI, NESS, ALMA…
ØESTEMA: legacy animations of circumstellar H2O and SIO masersüTracing dynamic mass loss events on week scale