1. No category

NRO High-z Legacy
B. Hatsukade / D. Iono (NAOJ),
& High-z Legacy team
NRO UM 2014/07/23-24
Membership
• NAOJ: D. Iono, B. Hatsukade, Y. Matsuda, R. Kawabe, K. Nakanishi,
Y. Ao, T. Kodama, M. Hayashi, K. Yabe, Y. Koyama, K. Tadaki
• U. Tokyo: K. Kohno, Y. Tamura, K. Motohara, S. Ikarashi, H.
Umehata, A. Tanigucuhi, Y. Yamaguchi, S. Fujimoto, J. Ueda, T.
Saito, Y. Kato, M. Lee, T. Michiyama, T. Saito, S. Yuma
• Kyoto U.: K. Ohta, A. Seko, K. Ichikawa, T. Takeuchi
• Nagoya U.: T. Nakajima
• Meisei U. / NAOJ: T. Kurahashi
• U. of Cambridge: K. Ota
Background
Submillimeter Galaxies
•
•
•
•
LFIR > 1013 L sun
SFR > 1000 Msun/yr
Dominated by starbursts
z>2-3
Problem
Redshift determination is difficult because of the
faintness of optical counterparts
CO redshift
Obtain secure redshifts of SMGs by blindly
detecting two consecutive CO J transitions
z=0
CO(2-1)
CO(1-0)
Iono et al. (2006)
CO(3-2) CO(4-3)
Z-machines around the world
Zspec on CSO: Lupu et al. (2010)
IRAM EMIR: Weiss et al. (2009)
GBT-zpectrometer:
Harris et al. (2012)
LMT-redshift search receiver: www.lmtgtm.org
ALMA as a z-machine
Weiss et al. (2013), Vieira et al. (2013)
Redshift Determination with 45m
• NRO new receiver (Tz) / spectrometer system
• Band width = 4 GHz (IF 4-8)
• multiple scans by changing center frequency
• High-z Legacyの目的
• これまで困難であった45mでのhigh-z天体の検出
• blind redshift determination
①
②
③
④
LSB
USB
4GHz
~25 GHz
High-z Legacy 2009-2010
• Commissioning Tz receiver and new system
• Used T100 but mainly non-detections due to
winding baselines
High-z Legacy 2011-2012
• Total allocated time: 452 hr (~30% efficiency)
• Observed 5 sources (3 detections, 1 tentative, 1 non-detection)
• On source = 5-11 hr
Flux Density (Jy)
• Tsys = 170-250 K
Iono et al. (2012)
High-z Legacy 2012-2013
• Total allocated time: 314 hr
• Observed 7 sources (1 tentative, 6 non-detection)
SSA22-AzTEC1
?
8 mJy SMG discovered by ASTE in
a z = 3.1 protocluster (Tamura+08)
- L(FIR) = 1.9e13 Lsun
- CO(3-2)@~84GHz
High-z Legacy 2013-2014
Target
Notes
z search
J1344
Extremely bright Herschel source
(collaboration with the H-Atlas group)
spec-z = 2.3
(CARMA detection)
from 2012
SSA22-AzTEC1
8 mJy SMG discovered by ASTE/AzTEC, semi-blind z search
followed up at SMA.
(photo-z ~ 3.1)
from 2012
SXDF850.6
4 mJy SMG discovered by ASTE/AzTEC, semi-blind z search
followed up at SMA.
(photo-z ~ 1.87)
(from 2012)
J0919
Bright Herschel source
(collaboration with the H-Atlas group)
blind z search
J1427
Bright Herschel source
(collaboration with the H-Atlas group)
blind z search
High-z Legacy 2013-2014
Total allocated time : 495 hr / Total observing time: ~207 hr
Total on-source time: ~78 hr / Total on-source time (after flag): ~26 hr
Time Allocation
J1344
• Bright Herschel source
• should be detected at ~4 mK (Ta*) at 104.76 GHz (private
communication)
• on-source time (after flagging): 47 min
• rms: 0.7 mK (Ta*)
• tentative detection
(see poster by T. Kurahashi)
SSA22-AzTEC1
• Bright AzTEC source with photo-z (z = 3.1)
• Semi-blind redshift search
• on-source time (after flagging): 27 min
• rms: 0.6 mK
?
2012-2013
Ta* (mK)
Ta* (mK)
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
5.0
0.0
2013-2014
(reduced by Y. Kato)
SXDF 850.6
•
•
•
•
•
Bright AzTEC source with photo-z (z = 1.87)
Semi-blind redshift search
on-source time (after flagging): ~1 hr
rms: 0.4-0.9 mK
non-detection
J0919
•
•
•
•
•
Bright Herschel source
Blind redshift search (4 spectral scans)
on-source time (after flagging): ~8 hr (~2 hr per scan)
rms: 0.2-0.4 mK
non-detection
--- scan 1 --- scan 2 --- scan 3 --- scan 4
J1427
•
•
•
•
•
Bright Herschel source
Blind redshift search (4 spectral scans)
on-source time (after flagging): ~16 hr (~4 hr per scan)
rms: 0.2-0.8 mK
non-detection
--- scan 1 --- scan 2 --- scan 3 --- scan 4
打率の低い要因
• Observed 5 (2 tentative, 3 non-detection)
• ベースラインのうねり
• 装置の不安定性
• 天気の要因
• 強いスプリアス
• ラインが弱く、検出限界以下?
• 10 mJy  ~1 mK (Ta*)
• 分光計でカバーしていない赤方偏移?
• photo-zのエラー
• 4 spectral scanでもカバーしきれない範囲がある
flag 0 %
??
??
flag 87 %
flag 98 %
High-z Legacy
• 結果
• 赤方偏移が既知の天体であれば検出可
• 一方、目標としていたblind redshift searchは困難
• 今後
• High-z Legacyは終了とする
• 共同利用枠に個々の天体の観測提案を申請する形
論文化・データ公開
• 論文
• Iono et al. 2012
• T. Kurahashi (in prep. 修論)
• データ公開
• raw data
• reduced data
• text file of the final spectrum
High-z Legacyの果たした役割
NRO new receiver/spectrometer systemの構築
 システムの性能評価
 測定手順の確立
 指示書作成ソフト zobs の開発
Galactic/extragalacticでの大規模spectral line surveyも可能
ALMAにつながる多くの成果が出ている
High-z天体のCO検出 (Iono et al. 2012)
45mでのhigh-z天体観測を可能に
 observed 16 (4 detection, 2 tentative, 10 non-detection)
 赤方偏移が既知の天体であれば検出可
他機関・他分野との連携
学生の教育