论文标题
Dorado及其成员星系。 iii。用紫外线的fuv成像映射星形形成
Dorado and its member galaxies. III. Mapping star formation with FUV imaging from UVIT
论文作者
论文摘要
我们正在研究积极发展的Dorado组的星系中的SF，其中ETG和LTG中的光学和无线电观察结果揭示了相互作用和合并事件的特征。我们以前的HA+[NII]研究探测了约10个MYRS时标，这表明SF仍在进行ETG中。在这项工作中，我们使用Far-UV（FUV）成像在大约100 myrs的时间尺度上绘制最新的SF。我们在Astrosat上使用了紫外线望远镜紫外线，以图像先前在HA+[NII]中观察到的Dorado骨干星系，并带有Far-UV Filter Fuv.caf2（1300-1800A）。该样本包括NGC1536，NGC1546，NGC1549，[CMI2001] 4136-01，NGC1553，IC2058，PGC75125，NGC1566，NGC1596，NGC1596和NGC1602。 FUV.CAF2发射在所有星系中均显示出来，追踪环中的年轻恒星种群并显示出潮汐变形。通过拟合亮度曲线得出的刻度指数始终是n <3，这表明fuv.caf2发射也源自ETG中的磁盘。 SFR的范围从[CMI2001] 4136-01的0.004+-0.001 m_sol yr^{ - 1}到2.455+-0.027 m_sol yr^{ - 1} NGC 1566的NGC 1566。对于这些星系，除边缘IC 2058外，比率sfr_ha/sfr_fuv.caf2接近1，与以前报道的本地体积样本的关系类似。但是，对于ETG，SFR_HA比SFR_FUV高15倍。 Dorado's ETGS在SFR_FUV的SFR_HA空间中定义了一个单独的基因座，相对于LTGS，它以关系日志（sfr_fuv.caf2）= 0.70xlog（sfr_ {ha}） - 1.26。从HA和FUV通量衍生的SFR之间的系统差异表明，ETG中的复兴发作无法维持超过约100个MYRS时标的SF。
We are investigating the SF in galaxies of the actively evolving Dorado group where signatures of interactions and merging events are revealed by optical and radio observations in both ETGs and LTGs. Our previous Ha+[NII] study, probing ~10 Myrs timescales, suggested that SF is still ongoing in ETGs. In this work, we use far-UV (FUV) imaging to map recent SF on times scales of about 100 Myrs. We used the Ultraviolet telescope UVIT on board Astrosat to image the Dorado backbone galaxies previously observed in Ha+[NII], with the far-UV filter FUV.CaF2 (1300-1800A). The sample includes NGC1536, NGC1546, NGC1549, [CMI2001]4136-01, NGC1553, IC2058, PGC75125,NGC1566, NGC1596 and NGC1602. FUV.CaF2 emission is revealed in all galaxies, tracing young stellar populations in rings and showing tidal distortions. The Sersic index, derived by fitting the luminosity profiles, is always n<3 suggesting that the FUV.CaF2 emission originates from a disk also in ETGs. The SFR ranges from 0.004+-0.001 M_sol yr^{-1} of [CMI2001]4136-01 to 2.455+-0.027 M_sol yr^{-1} of NGC 1566. Most of the recent SF is found at the periphery of the Dorado group where most of LTGs are located. For these galaxies, the ratio SFR_Ha/SFR_FUV.CaF2 is close to 1, except for the edge-on IC 2058, similarly to previously reported relations for Local Volume samples. For ETGs, however, SFR_Ha is about 15 times higher than SFR_FUV. The Dorado's ETGs define a separate locus in SFR_FUV, SFR_Ha space with respect to the LTGs, which is well represented by the relation log (SFR_FUV.CaF2) = 0.70xlog (SFR_{Ha})-1.26.The disk structure of the FUV.CaF2 emitting populations discovered in all the ETGs implies dissipative processes and wet merging events. The systematic discrepancy between SFRs derived from Ha and FUV fluxes suggests that rejuvenation episodes in ETGs cannot sustain constant SF over ~100 Myrs timescales.
