Post on 22-Mar-2016
description
Detection of Most Distant Type-Ia Supernova Remnant Shell as Absorption Lines in the Spectra of Gravitationally Lensed QSO B1422+231
Satoshi Hamano (University of Tokyo)
Collaborator:N. Kobayashi (Univ. of Tokyo), S. Kondo (Kyoto Sangyo Univ.), T. Tsujimoto (NAOJ), K. Okoshi (Tokyo Univ. of Science), T. Shigeyama (Univ. of Tokyo, RESCUE)
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Table of Contents1. Introduction
◦ QSO absorption-line systems◦ Gravitationally lensed QSOs
2. Observation◦ Target: B1422+231◦ Observation with Subaru IRCS
3. Results & Discussion◦ MgII absorption lines at z=3.54◦ The origin: type-Ia supernova remnant ?
4. Summary & Future Prospects◦ Preliminary results of our recent observation using
AO188
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1. Introduction
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QSO absorption-line systems
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“QSO absorption-line systems” are gas clouds that give rise to absorption lines in the spectrum of background quasars.
They are an only tool that can trace high-z gas clouds without bias of luminosity. 4
MgII systemsDoublet absorption lines of MgII (λλ2796, 2803) is the best lines to trace gas clouds associated with high-z galaxies. MgII systems can be detected in wide redshift range. MgII systems can trace various type of gas clouds in a wide
range of HI column density. 1015<N(HI)<1021 (Churchill+05)
MgII systems provide us precious information on the chemical and kinematical properties of high-z gas clouds. Processes of galaxy formation that stars are formed from
gas clouds are expected to be traced directly. (Kacprzak+11)
Complementary to the surveys of high-z galaxies with deep imaging.
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Difficulty of “single” line of sight of QSO
Observables from a set of absorption lines ◦ Column densities, temperature◦ Chemical abundances, metalicity
Non-observables because we observe them with just a single line of sight. ◦ Extent of gas clouds◦ Mass, volume density
The spatial structure of gas clouds is known to be one of a key parameters in galaxy formation theories. (Mo+99, Maller+04)
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QSOObserver? How large in
size or mass ?
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Lensing galaxy
QSO
Gas cloud
observer
“Multiple” lines of sight of gravitationally lensed QSOsMerits of gravitationally lensed QSOs (GLQSOs) Split of images
◦ We can observe multiple points of intervening gas clouds, which give us information of the spatial structure.
Magnification of images◦ We can resolve the structure of
gas clouds in small scale even at high redshift.
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“Effective” spatial resolution reaches just 1 mas !
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Optical ←|MgII lines| →Near-infrared
observer
Spatial structure of MgII systems examined with GLQSOs
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kpc-scale structure・ distribution of metal in halos/disks・ velocity field
lensing galaxy QSO
large separation
Past studies Our study
Possible with near-infrared high-dispersion spectroscopy Kobayashi+ (02), Hamano+ (12)
Many studies have been done by high-dispersion observation with optical and UV spectroscopy Rauch+ (00,01,02),Ellison+ (04) Lopez+(97,05),Monier+ (97,09), etc..
lower-z
small separation
higher-z
pc-scale structure・ geometry, size・ origin (HVC,SNR,HII region)
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z=2.5
Our purposeIn summary, our purpose is to investigate molecular clouds scale structure of high-z gas clouds traced by MgII systems at z>2.5 using multiple lines of sight of GLQSOs with near-infrared spectroscopy. In this talk, I will show you a first result of our on-going study of “GLQSO absorption-line systems” with Subaru IRCS. (Hamano+12)
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2. Observation
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TargetB1422+231 z=3.628 (Rauch+99) Four images and a lensing galaxy Have the 2nd brightest luminosity in NIR
among QSOs ever detected Known to have QSO absorption-line
systems at z>2.5 (Rauch+99, 00, 01). Due to the configuration, a very large
magnification can be achieved at higher redshift.
This object is the most appropriate for our study.
Closest images, A and B (AB=0.5 arcsec), are observed this time.
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Lensing galaxy(z = 0.339,Tonry 98)
0”.5
Slitviewer image of B1422+231 obtained by Subaru IRCS w/ LGSAO188
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Telescope Subaru telescope
◦ 8.2 m diameter◦ Known to have excellent stellar
images among ground-based telescopes→ Best to resolve close lensed images of GLQSOs( ~ 0.5 arcsec)
IRCS(Infrared Camera and Spectrograph)◦ We used NIR echelle mode (high spectral resolution)
→MgII absorption lines at z>2.5 can be observed
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IRCS
Subaru telescope
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Observation & Analysis Open-use observation by N.Kobayashi
◦ Wavelength : 1.01-1.38 μm (zJ & J bands)◦ Date : Feb. 13, 2003 ( zJ ),
Apr. 28, 2002 ( J )◦ AO36 was used only for zJ band observation.◦ Resolution : R=5,000 ( zJ ) , R=10,000 ( J )◦ Time : 9,000 sec ( zJ ) , 9,600 sec ( J )◦ Seeing : 0.3 arcsec (excellent !!)◦ Weather condition : photometric
Data was reduced with IRAF.
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0”.5
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Obtained data
3. Results & Discussion
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Resolved spectra of B1422+231
Spectra of images A and B of B1422+231
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Telluric absorption lines
z=3.54 MgII doublet
MgII emissionof QSO itself
Very small separation between images A and B :AB = 8pc @ z=3.54 corresponds to 1 mas
z=3.54 FeII lines
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Resolved spectra of B1422+231Absorption lines at z=3.54 MgII absorption lines
◦ Two components are detected with separation of ~ 200 km/s for both images.
◦ Differences of absorption lines can be seen between A and B for both components.
FeII absorption lines◦ Only one component of image A
is detected with large Doppler width. MgI absorption lines
◦ No detection
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These absorption lines reflect pc-scale gaseous structure at high redshift.
Since now, we will discuss the structure and origin of the z=3.54 system.
AB
A
C
CII
Past study of the z=3.54 system
Rauch+99 Optical obs. w/ Keck HIRES (R~45,000)
◦ Images A and C are observed( AC=22pc @ z=3.54)
◦ 2 velocity components are detected with low-ionization absorption lines (CII, SiII, etc.)
Symmetric profiles◦ Unique feature◦ Much difference of column
densities between images A and C◦ Velocities expand symmetrically
from image A to image C
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By what type of gas clouds are these unique profiles produced ?
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AC
CII
Past study of the z=3.54 system
Interpretation of the z=3.54 system by Rauch+99 Explanation of differences
by a expanding shell. Limit the expanding velocity
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A
CB
Newly observed
skmv /98
Is spectrum of image B consistent with this model ?
Outer shell produces stronger lines with smaller velocitiesInner shell produces weaker lines with larger velocities
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QSOobserver
Our observation
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A
CB
CII
C
AA,B : MgIIC : CII
MgII absorption lines in the spectrum of image B is found to have intermediate column densities and velocities of those of images A and C
Our observation supports the expanding shell model proposed by Rauch+99, qualitatively.
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3D spherically expanding shell modelIn order to constrain the size of the shell combining information from three images, we calculated a simple model of a 3-dimensional symmetric expanding shell with radius R and expanding velocity of v.
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AA vv cos2
AA Rd sin
Two geometrical equations on ⊿OAB, OBC
8 equations9 variables :
,,,,,,,, CBACBA dddvR
(Rauch+ 02)
R(v) can be obtained20
What is the z=3.54 system? (1)R-v relation of the z=3.54 system in comparison with Galactic objects having an expanding shell structure.
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(Koo+ 91)
Consistent with SNR21
Images must be located near the edge of the shell
The diameter must be exactly equal to the separation A-C.
Most likely!!
What is the z=3.54 system? (2)Estimate of fundamental parameters of the z=3.54 system Estimate mass of shell using the value of MgII column
density
Under the assumption that the z=3.54 system is a SNR, using sedov-phase solution,◦ Age:◦ Density of interstellar medium :
◦ Energy of supernova :
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oo MMM 18847
ergEerg 500
49 102.3108.3
yrtyr 55 102.2101.1
330
33 106.3108.1 cmncm
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All of these parameters are consistent with typical values of Galactic SNRs (Koo+91), suggesting the z=3.54 system is truly a SNR.
Type of the SNR at z=3.54 (1)Abundance ratio Comparison of [MgII/FeII]
with low-z MgII systems (Narayanan+07)
[MgII/FeII] of the z=3.54 system is near to those of Fe-rich systems.
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z=3.54 system
MgII column density
log[MgII/
FeII]
Low-z MgII systems
solar
■Confirmed Fe-rich systemsFeII rich
Type-Ia SN enrichment (Rigby+02)
The z=3.54 system is a remnant produced by a type-Ia supernova
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Type of the SNR at z=3.54 (2)Gas kinematics Broad FeII absorption line
◦ b(FeII) = 23±6 km/s◦ b(MgII) = 9±1 km/s
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Perturbed FeII-rich gasejected by SN explosion.
Conclusion:The z=3.54 system is themost distant type-Ia SNR
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4. Summary & Future Prospects
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Summary We obtained spatially-resolved NIR spectra of images
A and B of a GLQSO, B1422+231 with Subaru IRCS. We detected MgII and FeII absorption lines at z=3.54
with systematical differences between images A and B, whose separation at the redshift is just an 8 pc.
From expanding shell model, we concluded that the z=3.54 system is a type-Ia supernova remnant. It is the first case to identify the origin of a specific QSO absorption-line system.
The z=3.54 system is the most distant type-Ia supernova (remnant) ever detected (Most distant type-Ia supernova detected with light is at z=1.55: Conley+11).
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See Hamano et al., (2012, ApJ, 754, 88) for the detail of this study .
Future plan ~ LGSAO188 ~ We are advancing the NIR survey of MgII systems in
the spectra of GLQSOs with Subaru IRCS/LGSAO188.◦ LGSAO188 enables us to obtain high-quality
(higher spectral-, spatial-resolution, throughput) spectra of GLQSOs.
More GLQSOs at z>2.5 can be observedw/ higher throughput of LGSAO188for the first time.◦ Improved stellar images increase flux in a slit◦ We selected 7 brighter GLQSOs as
a first sample and we are observing them.
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LGSAO188 with Subaru.(from NAOJ homepage)
Preliminary results 2 GLQSOs (including B1422+231) have been already
observed using guaranteed time of AO188.
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Detected!
Profiles are slightly resolved!
Spectra of B1422+231 obtainedw/ IRCS/AO188 (NGS & LGS)
Spectra obtained w/o AO(this study)
As for the other observed object, we also detected some MgII systems with spatial structures.Analysis and observation are proceeding now!
R=10,000 R=20,000