銀河物理学特論 I銀河物理学特論Galactic Astrophysics I

I 5 E i i li Di tiI-5: Emission-line Diagnostics

2015/05/25

HII regions in M51M51 の HII 領域の 領域

HII region NGC604 in M33M33 の HII 領域 NGC604の 領域

Planetary Nebulae惑星状星雲惑星状星雲

Narrow-line / Broad-line regions of Active Galactic Nuclei活動銀河中心核の狭/広輝線領域活動銀河中心核の狭/広輝線領域

Emission line spectrum輝線スペクトル輝線 クトル

• Line ratio vary with ionizing photon spectrum.

Dominated by ions with low ionization degree.

Ionization source~10,000K、density 1000cm 3 Te 7 000density 1000cm-3、Te~7,000-25,000K

Dominated by highly ionized ions

Ionization source~100,000K、density 1000cm 3density~1000cm-3、Te~10,000K

Ions with various ionization states.

Ionization source~power-law continuum density~1000cm-continuum、density~1000cm-3、Te~10,000K

Photo-ionization Cross-section光電離の断面積光電離の断面積

• Photo ionization cross section peaks at the ionization energy and declines with E^-3. The energy range of photons which can ionize atoms (or ions) is

l ti lrelatively narrow.

“Atomic Astrophysics and Spectroscopy” Pradhan & Nahar 2011

Source of Ionizing photons電離光子の起源電離光子の起源

• Main sequence massive stars or white dwarfs

Iben 1967, ARAA, 5, 571Shaw & Kaler 1989, ApJS, 69, 495

Stellar effective temperature and number of ionizing photons星の有効温度と電離光子の数星の有効温度と電離光子の数

Sternberg et al. 2003, ApJ, 599, 1333

Structure of ionized regions: Hydrogen, Helium電離領域の構造電離領域の構造

Tielens “The Physics and Chemistry of the Interstellar Medium”

Structure of ionized regions: Oxygen, Nitrogen電離領域の構造電離領域の構造

Tielens “The Physics and Chemistry of the Interstellar Medium”

Classification of galaxies with emission line properties輝線の性質を用いた銀河の分類輝線の性質を用 た銀河の分類

[OII] Ha,NIIHb [OIII]

Tremonti et al. 2004, ApJ, 613, 898

Classification of galaxies with emission line properties輝線の性質を用いた銀河の分類輝線の性質を用 た銀河の分類

AGN

LINERLINERHII-region

AGNs tend to have stronger highly ionized emission lines, like [OIII]

Kauffmann et al. 2003, MNRAS, 346, 1055

Solid line ：selection line by Kewly et al. (2001) model calculation, Dashed line : empirical line.

Gas-phase metallicity estimation with emission lines輝線を用いたガス金属量の診断輝線を用 たガ 金属量の診断

• Gas phase metallicity can be evaluated with nebulae emission lines

Maiolino et al. 2008, A&A, 488, 463

Gas-phase metallicity estimation with emission lines輝線を用いたガス金属量の診断輝線を用 たガ 金属量の診断

• Mass-metallicity relation of nearby galaxies

Tremonti et al., 2004, ApJ, 613, 898

What does determine the observed relation between SMBH mass and “spheroid” mass ?SMBH mass and spheroid mass ?

Emission-line diagnostics in the nuclear region of galaxiesin the nuclear region of galaxies

Emission line diagnostics for star-forming galaxies星形成銀河の輝線診断星形成銀河の輝線診断

• Photo-ionization by OB stars.• Effects of metallicity and ionization y

parameter

Kewley et al. 2013, ApJ, 774, 100

Emission line diagnostics for star-forming galaxies星形成銀河の輝線診断星形成銀河の輝線診断

Kewley et al 2013 ApJ 774 100Kewley et al. 2013, ApJ, 774, 100

Emission line diagnostics for Active Galactic Nuclei活動銀河中心核の輝線診断活動銀河中心核の輝線診断

• Photo-ionization models of AGN continuum.

Kewley et al. 2013, ApJ, 774, 100y , p , ,

Emission lines from “shocked” regions衝撃波領域からの輝線放射衝撃波領域からの輝線放射

• Shock: models with collisional excitation of ions.• Precursor: photoionization by UV emission from shocked region.p y g• AGN/LINERs have similar line ratios to shock models.

Allen et al. 2008, ApJS, 178, 20

Comparison between different emission line models異なる輝線モデルの比較異なる輝線 デルの比較

Sarzi et al. 2010, MNRAS, 402, 2187

Emission line diagnostics of nuclear regions of nearby galaxies近傍銀河中心各領域の輝線診断近傍銀河中心各領域の輝線診断

• Emission line diagnostics of nuclear regions (~200pc) of galaxies in the nearby universe (<17Mpc).

Ho et al. 2008 ARAA, 46, 475

Emission line diagnostics of nuclear regions of nearby galaxies近傍銀河中心各領域の輝線診断近傍銀河中心各領域の輝線診断

• Emission line diagnostics of nuclear regions (~200pc) of galaxies in the nearby universe (<17Mpc).

Ho et al. 2008 ARAA, 46, 475

Emission line diagnostics of nuclear regions of nearby galaxies近傍銀河中心各領域の輝線診断近傍銀河中心各領域の輝線診断

• LINERs are dominant population among nuclear region of early-type galaxies Ho et al. 2008 ARAA, 46, 475Ho et al. 2008 ARAA, 46, 475

What are LINERs ?LINER とは何かとは何か

• Some LINERs show broad-line component indicating existence of AGN activity.

Ho et al. 2008 ARAA, 46, 475

What are LINERs ?LINER とは何かとは何か

• Photo-ionization by post-AGB stars can be another ionization mechanism for LINERs.

Sarzi et al. 2010, MNRAS, 402, 2187