论文标题
见证$ l _ {*} $椭圆形的星形淬灭
Witnessing the star-formation quenching in $L_{*}$ ellipticals
论文作者
论文摘要
我们研究了$ l _ {*} $椭圆形星系在颜色尺度图中的演变，以了解其恒星形成历史和环境，以了解其淬火过程。我们已经从36500个星系样品中从视觉上提取的1109 $ L _ {*} $星系，这些星系是从Sloan Digital Sky Survey的Stripe82中选择的。从该样本中，我们根据其表面亮度配置文件选择了51个椭圆形，由单个S $ \ acute {e} $ rsic配置文件很好地安装，其中s $ \ acute {e} $ rsic indices $ 3 <n <6 $。我们的样本包括12个蓝云$ l _ {*} $椭圆形（ble），11 green-valley $ l _ {*} $椭圆形（gle）和28个红色序列$ l _ {*} $ eLLIPTICALS（rle）。我们发现，大多数Rle和Gles直到最近才被淬灭，或者仍基于它们的[{o \ sc {iii}}]和H $α$发射的恒星，而BLES则剧烈形成恒星。发现BLES中的恒星形成延伸到银河系上，而不局限于其中部地区。在$ l _ {*} $椭圆形的大约40％中，与[{o \ sc {iii}}]排放相比，与[{o \ sc {iii}}]排放相比，与[{o \ sc {ii}}}和h $ a $α$α均给出了A at A a fens a fens a fens A a fens A g n fess A a fens A g aft a fens A g an fens A at A g an fens A g aft a fens A at A g aft a fens A g aft a f in fess，我们还发现，星系颜色与宇宙 - Web环境相关，而BLE倾向于驻留在较低密度的区域，RLE更喜欢密度，簇状区域和在任何一个中发现的GLES。一种可能的情况是，随着恒星形成的椭圆形迁移到簇中，它们的恒星形成被热集群内介质窒息而死。
We study the evolution of $L_{*}$ elliptical galaxies in the color-magnitude diagram in terms of their star-formation history and environment, in an attempt to learn about their quenching process. We have visually extracted 1109 $L_{*}$ galaxies from a sample of 36500 galaxies that were spectroscopically selected from Stripe82 of the Sloan Digital Sky Survey. From this sample we have selected 51 ellipticals based on their surface-brightness profile being well-fitted by a single S$\acute{e}$rsic profile with S$\acute{e}$rsic indices $3<n<6$. Our sample consists of 12 blue-cloud $L_{*}$ ellipticals (BLE), 11 green-valley $L_{*}$ ellipticals (GLE), and 28 red-sequence $L_{*}$ ellipticals (RLE). We find that most of the RLEs and GLEs have been quenched only recently, or are still forming stars, based on their [{O\sc{iii}}] and H$α$ emission, while the BLEs are forming stars vigorously. The star-formation in BLEs is found to be extended over the galaxy and not confined to their central region. In about 40\% of the $L_{*}$ ellipticals (ten BLEs, four GLEs and five RLEs), star-formation quenching seems to have started only recently, based on the lower [{O\sc{iii}}] emission compared to the [{O\sc{ii}}] and H$α$ emission, at a given metallicity. We also find that the galaxy color is correlated with the cosmic-web environment, with the BLEs tending to reside in lower-density regions, the RLEs preferring denser, clustered regions, and the GLEs found in either. One possible scenario is that as the star-forming ellipticals migrate into the clusters, their star formation is suffocated by the hot intra-cluster medium.
