Evolutionary Transition of Galaxies

星系的演化转变

• 批准号: 09640311
• 负责人: ARIMOTO Nobuo
• 金额: $ 2.3万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640311/
• 关键词: Galaxy Evolution; Galaxy Formation; Evolutionary Transition; Stellar Population; Spectral Evolution; Chemical Evolution; Elliptical Galaxies; QSO; 遠赤外; ダスト; 銀河進化; 元素合成; 銀河団; 星生成

An evolutionary transition of galaxies is defined as a sudden decline of star forming activity in young galaxies. We have built up an evolutionary model of galaxy spectra and have applied it to elliptical galaxies in clusters. We find that color-magnitude (CM) relation of elipticals is due to a systematic variation of mean stellar metallicity as a function of galaxy luminosity which could be best explained by a galactic wind model. We find that evolution of the CM relation strongly depends on an epoch of major star formation. A detailed comparison of our model CM relation with those of elliptical galaxies in clusters at different redshifts strongly suggests that these galaxies should have formed at zィイD2FィエD2 > 2.5 - 4.We measured equibalent widths of several metallic lines in high redshift (z 〜 3 - 4) quasars and found very strong iron emission there. This suggests that at least interstellar matter of host galaxies of these quasars was already enriched by ejecta of type Ia supernovae. … More Thus, galaxies at these redshifts are older than SNIa progenitors, a typical lifetime of which is around 1.5 Gyr. This means the host galaxies of these quasars, very likely elliptical galaxies, formed at zィイD2FィエD2 > 5 - 9.Simple calculation of CO luminosity of cluster ellipticals, based on our CM relation analysis, indicates that CO luminosity during actively star forming phase must be high enough to be detected by radio telescope. This reasonablly explains why we can detect CO in a quasar at z = 4.6, if the host galaxy is an elliptical before the onset of evolutionary transition.From these results, we conclude that the evolutionary transition in elliptical galaxies occurred at z 〜 4 - 5, possibly due to a galactic wind.With a hope that in near future submillimeter observations will become more easier and we will be able to get more spectra of galaxies in these wavelength region, we have newly built up an evolutionary model of galaxy spectra in which effects of dust absorption and re-emission are fully taken into account. We have applied the model to nearby star burst galaxies and are successful in desentagling age and dutiness from the observed optical-nearinfrared and farinfrared colours. Since primeval galaxies at high redshifts would be very similar to those nearby starburst galaxies, we believe that we have established a way to derive the age of these high redshift galaxies without any uncertainties. This would eventually lead us to estimate the epoch of formation of these primival galaxies. Less

星系的演化转变被定义为年轻星系中星星形成活动的突然下降。我们建立了星系光谱的演化模型，并将其应用于星系团中的椭圆星系。我们发现椭圆星系的色-星等关系是由于平均恒星金属丰度随星系光度的系统变化而产生的，这可以用星系风模型来解释。我们发现CM关系的演化强烈依赖于主要星星形成的时代。我们的模型CM关系与不同红移星系团中椭圆星系CM关系的详细比较表明，这些星系应该形成于z_（10）D_（2F）D_（2D）> 2.5 - 4。我们测量了高红移（z_（10）3 - 4）类星体中几条金属线的等宽，发现那里有很强的铁发射。这表明，至少这些类星体的宿主星系的星际物质已经被Ia型超新星的喷出物所富集。 ...更多信息 因此，处于这些红移的星系比SNIA祖先更古老，其典型寿命约为1.5 Gyr。这意味着这些类星体的宿主星系，很可能是椭圆星系，形成于z_（10）D_2 F_（10）D_2> 5 - 9。基于CM关系分析，对椭圆星系团CO光度的简单计算表明，在活跃的星星形成阶段，CO光度必须足够高，才能被射电望远镜探测到。这合理地解释了为什么在z = 4.6的类星体中，如果宿主星系在演化转变开始之前是椭圆星系，我们就能探测到CO，由此我们得出结论：椭圆星系的演化转变发生在z = 4.5，可能是由于银河风。希望在不久的将来，亚毫米波观测将变得更加容易，我们将能够获得更多的在此基础上，我们建立了一个充分考虑尘埃吸收和再发射效应的星系光谱演化模型。我们已将该模型应用于附近的星星爆发星系，并成功地从观测到的光学近红外和远红外颜色的年龄和dutiness。由于高红移的原始星系与附近的星暴星系非常相似，我们相信我们已经建立了一种方法来获得这些高红移星系的年龄，而没有任何不确定性。这将最终导致我们估计这些双星系的形成时代。少

项目成果

Y.Taniguchi,T.Murayama,N.Arimoto etc: "the most distant OIII emitting quasar PKS1937-101 at redshift 3.8"Publ.Astron.Soc.Japan. 49. 419-424 (1997)

Y.Taniguchi，T.Murayama，N.Arimoto等：“最远的OIII发射类星体PKS1937-101，红移3.8”Publ.Astron.Soc.Japan。

Y.Taniguchi,N.Arimoto他: "The most distant 〔0III〕 amitting Quasar PKS 1937-101 at Z=3、8" P.A.S.J.49. 419-424 (1997)

Y.Taniguchi、N.Arimoto 等人：“最远的 [0III] 位于 Z=3, 8 处的类星体 PKS 1937-101”P.A.S.J.49 (1997)。

Ishimaru,Y., ARIMOTO,N.: "Roles of SNIa SNII in ICM Enrich ment" Pabl.Astron.Soc.Japan. 49. 1-8 (1997)

Ishimaru,Y.，ARIMOTO,N.：“SNIa SNII 在 ICM 丰富中的角色”Pabl.Astron.Soc.Japan。

Murayama,N.Arito,Y.Taniguchi etc: "Near infrared spectroscopy of the high z quasar S40636+68 at z=3.2"Astronomical Journal. 115. 2237-2243 (1998)

Murayama，N.Arito，Y.Taniguchi 等：“z=3.2 处高 z 类星体 S40636 68 的近红外光谱”天文学杂志。

Kodama, T., Arimoto, N.: "Secondary Episode of Star Formation in Elliptical Galaxies"Mon. Not. Roy. Astr. Soc.. 334. 99-109 (1998)

Kodama, T., Arimoto, N.：“椭圆星系中恒星形成的第二阶段”周一。