Gas-to-Dust Ratio of Massive Star-Forming Galaxies at z~1.5 (II)
世古 明史
京都大学 D1
共同研究者
太田 耕司 (京都大学)
廿日出 文洋, 矢部 清人, 伊王野 大介 (国立天文台)
銀河進化と星間物質
銀河進化＝ガスから星への転換史
ON NORMALIZATION OF COSMIC SFH
星形成率密度
et al. (2006). A parallel set of assumptions to step (2) regarding
- z 2前後で宇宙における
星形成は最も活発
・分子ガス
- 星形成の母体
星形成率密度
the generation of SNe Ia lead to predictions for the SN Ia rate
density, and this is explored in some detail with tantalizing implications regarding the extent of the SN Ia delay time.
In x 2 we update the SFH data compilation of Hopkins (2004)
and address some of the assumptions that affect the normalization.
We identify the best parametric fit to the most robust subset of this
data in x 3, consistent with the e limits from SK. In x 4 we present
the results of this fitting in terms of the stellar and metal mass
density evolution and the SN II and SN Ia rate evolution. The implications for the assumed IMF and SN Ia properties are discussed
further in x 5.
The 737 cosmology4 is assumed throughout, with H0 ¼
70 km sÀ1 MpcÀ1, M ¼ 0:3, and à ¼ 0:7 (e.g., Spergel et al.
2003).
2. THE DATA
0
赤方偏移 : z
1
2
3
143
4 5 6 7
0.1
0.01
Hopkins & Beacom 2006
Fig. 1.— Evolution of SFR density with redshift. Data shown here have been
scaled, assuming the SalA IMF. The gray points are from the compilation of
Hopkins (2004). The hatched region is the FIR (24 m) SFH from Le Floc’h
et al. (2005). The green triangles are FIR (24 m) data from Pe´rez-Gonza´lez et al.
(2005). The open red star at z ¼ 0:05 is based on radio (1.4 GHz) data from
Mauch (2005). The filled red circle at z ¼ 0:01 is the H estimate from Hanish
et al. (2006). The blue squares are UV data from Baldry et al. (2005), Wolf et al.
(2003), Arnouts et al. (2005), Bouwens et al. (2003a, 2003b, 2005a), Bunker et al.
(2004), and Ouchi et al. (2004). The blue crosses are the UDF estimates from
Thompson et al. (2006). Note that these have been scaled to the SalA IMF,
assuming they were originally estimated using a uniform Salpeter (1955) IMF.
The solid lines are the best-fitting parametric forms (see text for details of which
data are used in the fitting). Although the FIR SFH of Le Floc’h et al. (2005) is not
used directly in the fitting, it has been used to effectively obscuration-correct the
UV data to the values shown, which are used in the fitting. Note that the top
logarithmic scale is labeled with redshift values, not (1 þ z).
・ダスト
- 星形成に適する環境をつくる (H2形成, cooling)
The compilation of Hopkins (2004) was taken as the starting
point for this analysis, shown in Figure 1 as gray points. These
data are reproduced from Figure 1 of Hopkins (2004) and use
their ‘‘common’’ obscuration correction where necessary. Additional measurements are indicated in color in Figure 1. For
z P 3, these consist of FIR (24 m) photometry from the Spitzer
Space Telescope ( Pe´rez-Gonza´lez et al. 2005; Le Floc’h et al.
2005) and UV measurements from the SDSS (Baldry et al. 2005),
GALEX (Arnouts et al. 2005; Schiminovich 2005), and the
COMBO17 project (Wolf et al. 2003). At z ¼ 0:05, a new radio
(1.4 GHz) measurement is shown (Mauch 2005), which is highly
consistent with the FIR results, as expected from the radio-FIR
correlation (Bell 2003a). Also at low redshift (z ¼ 0:01) is a new
遠方にある一般的な星形成銀河の
ガス・ダスト比はよく分かっていない
ガス・ダスト比の赤方偏移進化｜理論
100
理論モデル計算
t=0-12Gyr で Mgas, Mdust が
どう変化するか
ガスの収支
dMgas
=
dt
(1
⌘Mgas
R)
+ F
⌧SF
inflowで供給
(1
dMman
=
dt
赤方偏移進化
10
1
1
0.5
0.1
0
0.1
⌘MZ
⌘Mgas
R)
+ yZ
+ Zin F
⌧SF
⌧SF
inflow
ダストの収支
dMcor
=
dt
2
星形成で消失
金属量の収支
dMZ
=
dt
ガス・ダスト比
z=3
星形成で消失
⌘Mcor
⌧SF
金属量
1
※縦軸・横軸ともMWの値で規格化
星で生成
Inoue 2003 を改変
Mcor
⌘MZ
⌘Mgas
Mcor (1
+ fc (R
+ yZ
) + ⇠
⌧SN
⌧SF
⌧SF
⌧acc
SNで破壊
Mman
+ (1
⌧SF
Mcor (1
⇠)
⌧acc
cl )
星で生成
降着成長
cl )
降着成長
観測天体
SXDS領域 & COSMOS領域
- spec-z（Hα with Subaru/FMOS）
- solar metallicity → αCO = 4.36 Msun/(K km/s pc2)
- Herschel/SPIRE 250, 350μmで検出 → Mdust
(Spitzer/MIPS 24μmでも検出)
L⇥(rest)
Mdust =
4⇤
⇥ B⇥(rest)
h (rest)
kB Tdust
c L⇥(rest) (e
=
3
8⇤ 0 h⇥(rest)
2
1) ⇥(rest)
(
)
⇥125µm
= 1.5
Tdust = 35 K
12- 13シーズン
spec-z
M★
SXDS1_12778
1.396
5.6 1011
5.4 108
8.66
SXDS3_80799
1.429
1.1 1011
6.7 108
8.66
COSMOS_9
1.461
2.5 1011
3.4 108
＜8.68
COSMOS_9
1.461
2.5 1011
3.4 108
＜8.68
COSMOS_50
1.21
7.0 1010
4.5 108
8.84
[Msun]
Mdust
[Msun]
metallicity
13- 14シーズン
12- 13シーズン結果｜Seko et al. (2014) in press
Tmb [mK]
4
2
0
-2
0
400
速度 [km/s]
-400
-400
0
400
-400
0
400
赤方偏移進化は
あまり見られない
100
ガス・ダスト比
−1 −1
−1km
1. CO(2-1)
spectra
taken
with
the
Nobeyama
45m
telescope
binned
svelocity
velocity
width.
1. CO(2-1)
spectra
taken
with
the
Nobeyama
telescope
binned
50 km
svelocity
width.
Fig.Fig.
1.Fig.
CO(2-1)
spectra
taken
with
the
Nobeyama
45m45m
telescope
binned
withwith
50with
km
s50
width.
z=3
stacked
spectrum
Arrows
show
the
velocity
zero
points
for
CO
lines
expected
from
spectroscopic
redshifts
by Hα
observations.
Arrows
show
the
velocity
points
for CO
lines
expected
spectroscopic
redshifts
by Hα
observations.
Arrows
show
the
velocity
zerozero
points
for
CO
lines
expected
fromfrom
spectroscopic
redshifts
by Hα
observations.
Horizontal
bars
show
the
uncertainty
of the
velocity
zero
points.
Horizontal
show
the
uncertainty
of the
velocity
points.
Horizontal
barsbars
show
the
uncertainty
of the
velocity
zerozero
points.
2
Tmb [mK]
4
2
0
-2
10
1
1
0.5
0.1
0
-400
0
速度 [km/s]
0.1
400
−1
金属量
1
※縦軸・横軸ともMWの値で規格化
13- 14シーズン観測
COSMOS_9
1.461
2.5 1011
3.4 108
＜8.68
COSMOS_50
1.21
7.0 1010
4.5 108
8.84
・野辺山45m宇宙電波望遠鏡
・2014年 3月22-25日
・観測輝線
：CO(J=2-1)
・観測周波数 ：93.7, 104.3 GHz
・受信機
：TZ 1V/H, 2V/H
・Tsys
：130-170 K
・積分時間
：3h28m, 2h22m
・rms noise ：0.3, 0.6 mK
13- 14シーズン結果
COSMOS_50
6
6
4
4
2
Tmb [mK]
Tmb [mK]
COSMOS_9
0
2
0
-2
-2
-4
-4
-400
0
速度 [km/s]
M(H2) ＜ 5.0
1010
400
Msun
-400
0
速度 [km/s]
400
M(H2) ＝ 9.6 1010 Msun
fgas ＜ 0.27
fgas ＝ 0.58
ガス・ダスト比 ＜ 150
ガス・ダスト比 ＝ 210
＜ 0.9
(MWの値で規格化)
＝ 1.3
(MWの値で規格化)
13- 14シーズン結果
100
赤方偏移進化は
あまり見られない
z=3
ガス・ダスト比
2
10
1
1
0.5
0.1
0
0.1
1
金属量
ダストの早い降着成長
8
7
⌧acc = 10 yr
⌧acc = 10 yr
100
100
ガス・ダスト比
z=3
z=3
2
10
10
2
1
1
1
0.5
1
0.5
0.1
0.1, 0
0
0.1
金属量
1
0.1
金属量
1
※縦軸・横軸ともMWの値で規格化
Inoue 2003 を改変
ダストの早い降着成長
8
7
⌧acc = 10 yr
⌧acc = 10 yr
100
100
ガス・ダスト比
z=3
z=3
2
10
10
2
1
1
1
0.5
1
0.5
0.1
0.1, 0
0
0.1
金属量
1
0.1
金属量
1
※縦軸・横軸ともMWの値で規格化
Inoue 2003 を改変
τacc∼107 yrの降着成長を考えると説明可能
まとめと今後
・z 1.5にある星形成銀河のCO(J=2-1)観測 → Mgas
Herschelで検出 → Mdust
solar metallcity → αCOの不定性 小
目的 ガス・ダスト比の赤方偏移進化の観測的検証
結果 赤方偏移進化はほとんど見られない
→ ダストの降着成長の早さ ∼ 107 yr
・ 12- 13シーズン未検出天体の検出
・ガス・ダスト比のscatter