Probing radial position wander of blazar Mrk 501 core with VLBI

Probing radial position wander of blazar Mrk 501 core with VLBI

Probing radial position wander of
blazar Mrk 501 core with VLBI
jet
radio core
black hole
@NAOJ/AND You Inc.
Shoko Koyama (The University of Tokyo/NAOJ)
M. Kino, A. Doi (ISAS), H. Nagai (NAOJ), K. Niinuma (Yamaguchi Univ.),
M. Honma (NAOJ), T. Oyama (NAOJ), K. Hada (IRA), K. Akiyama (NAOJ),
M. Giroletti (IRA), G. Giovannini, M. Orienti (Bologna Univ.), N. Isobe (ISAS),
1
K. Asada (ASIAA), J. Kataoka (Waseda Univ.), D. Paneque (Stanford Univ./SLAC)
Locations between BH & radio core
Rbh-core~14-23Rs~0.01pc
BH
43GHz radio core
M87 by Hada+11
Rbh-core~105Rs~ a few pc
BH
multi-freq. core shift
+VLBI phase referencing
àposition accuracy ~beam/10
43GHz radio core
blazars by Marscher+08
time lag method
•  The locations of blazar radio cores have not been
studied with enough positional accuracy
•  Blazar radio cores may wander because they locate far
from the BH
Our method:The locations of blazar radio
core based on internal shock model
radio core
BH
Γf,1
Γs,1
Γ f+s,1
Ifs
DIS,1
% Γ s,1 (
4
DIS,1 ≈ 5 ×10 Rs ⋅ '
*
& 50 )
2
% I fs (
'
*
& 10Rs )
Purpose: constrain on the jet lorenz factor Γs,1,
which decide the position of radio core
Method: Explore the radio core wander by using
phase referencing with single freq. & at multi epochs
Target : Mrk 501
HSA
~600pc
GMVA VLBA
~1pc
~0.1pc
Giroletti+08
•  One of the closest blazars　(1mas=0.66pc=7x10^4Rs)
•  viewing angle 4~15 deg (Giroletti+04)
•  X-rays and Very High Energy (VHE) emission show
very fast variability (tvar~a few min.) (Albert+07)
•  no superluminal motions were detected (Giroletti+04)
SED of Mrk 501 Fermi MWL campaign in 2009 Abdo+2011
ν Fν [erg cm -2 s -1]
The Astrophysical Journal, 727:129 (26pp), 2011 February 1
Abdo et al.
10-9
SMA
-10
10
VLBA(BP143)
Swift/BAT
VLBA_core(BP143)
RXTE/PCA
VLBA_core_ellipsefit(BP143)
Swift/XRT
VLBA(BK150)
VLBA_core(BK150)
Noto
averaged VLBI spectrum
Metsahovi
Medicina
10-11
VLBA(MOJAVE)
VLBA_Core(MOJAVE)
OVRO
RATAN
UMRAO
Effelsberg
-12
10
MAGIC
Swift/UVOT
BradfordRoboticTelescope
VERITAS
GASP
VERITAS_flare
GRT
10-13
Fermi
MITSuME
ROVOR
WIRO
OAGH
CampoImperatore
10-14
10
10
1012
1014
16
10
18
10
20
10
1022
1024
10
10
Giroletti+08
ν [Hz]
26
28
Figure 8. SED for Mrk 501 averaged over all observations taken during the multifrequency campaign performed between 2009 March 15 (MJD 54905) and 2009
August 1 (MJD 55044). The legend reports the correspondence between the instruments and the measured fluxes. Further details about the instruments are given in
Section 5.1. The optical and X-ray data have been corrected for Galactic extinction, but the host galaxy (which is clearly visible at the IR/optical frequencies) has not
been subtracted. The TeV data from MAGIC and VERITAS have been corrected for the absorption in the EBL using the model reported in Franceschini et al. (2008).
The VERITAS data from the time interval MJD 54952.9–54955.9 were removed from the data set used to compute the average spectrum, and are depicted separately
in the SED plot (in green diamonds). See the text for further details.
VLBI core would be optically thin above 8 GHz!
VLBI observations at 43 GHz
VLBA : 2012February~ 4 hr X 6 epochs (on going)
VERA : 2011February & October
8 hr X 4 successive days = 1 set
1659+399
3C 345
1.46°
target
2.09°
2.58°
0.49°
NRAO 512
Mrk 501
6
Swift/BAT Hard X-ray monitor and
our observation of Mrk 501
50days
2012/3/16
2012/6/11
2011/10 2012/2/12
2012/5/6
x-ray flare
(Atel#3752)
VERAß
àVLBA
@swift web
7
VERA data reduction flowchart
A beam: 1IF,3C 345
B beam: 15IF, NRAO512+Mrk501
UVW recalculation(A-apply2A)
Dual beam phase calibration(B_MINUS.1111)
CLCAL
CLCAL
ACCOR
CLCAL
CLCAL
APCAL
UVW recalculation(B-apply2B)
CLCAL
ACCOR
CLCAL
APCAL
FRING on NRAO512 (delay)
FRING
CLCAL
BPASS
SPLIT
FITTP
imaging
Copy 1IF solutions to 15IFs,
apply them to Bbeam
CLCAL
SN table
CLCAL
BPASS
Apply structure phase
SPLIT
FITTP
àfinal map
Apply amplitude solutionimaging
8
VERA images (e.g.,2011Feb.15)
Mrk 501 phase-ref. image
NRAO512 phase-ref. image
3C 345 self-cal image
We detect phase-referenced
target at SNR 7-14 for all data
9
VERA 7mm Astrometry Results
Y (mas)
Phase referenced core peak position of
Mrk 501 (reference:
NRAO512)
0.2
Prel
imin
arily
0.1
2011October
10,11,13,15
0
0.2
0.1
0
-0.1
-0.2
-0.3
-0.1
2011February
15,16,17,18
positional accuracy
per 1 epoch:160-180 uas
-0.2
à~1.5 pc (~10^4Rs) scale @Mrk501
atmospheric residual：~150 uas
-0.3
10
thermal
noise：~60
uas(=resolution/SN~10)
X (mas)
VERA 7mm Astrometry Results
Phase referenced core peak position of Mrk 501
(reference: NRAO512) 0.2
Prel
imin
arily
0.1
0
0.2
0.1
0
2011February
2011Octorber
-0.1
-0.2
-0.3
-0.1
-0.2
position accuracy per 1 set：80-90 uas
-0.3 50) ± 130 uas
àdeviation between 2 sets: (70,
11
àthe core peak positions are consistent within 2σ=260 uas
Discussion based on
internal shock model
t=t1
t=t2
Γf,1
Γs,1
DIS,1
Lshift<260 uas in source frame is
Γ f+s,1
Ifs
−1
#
&
L
#
&
θ
DIS,2 − DIS,1 < 5 ×10 4 Rs % shift (% min
 (
$ 260µ as '$ 4 '
Γ f+s,2
Γf,2
Γs,2
DIS,2
when DIS,2>>DIS,1,
DIS,2 − DIS,1 ≈ DIS,2 ≈ 2Γ 2s,2 I fs
−1
DIS,2-DIS,1
−1
" Lshift %" θ min % " I fs %
Γ s,2 < 40 $
'
'$  ' $
# 260µ as &# 4 & # 10Rs &
Lshift
During our observations, the lorenz factor of jet component
which decide core position would be below 40.
(Assume constant component ejection period)
Summary
•  We succeed in performing blazar core
astrometry with VERA 43GHz
•  During our observations, upper limit of the
core peak position is tentatively 260 uas
•  Based on internal shock model, radio core
is located within 5 pc from BH, and the
lorenz factor which decide the core position
is below 40
Future works
•  Discuss VERA and VLBA data together
•  Plan to use Italy+KVN+VERA