The WFC3 Infrared Spectroscopic Parallel (WISP) Survey
H. Atek, M. Malkan, P. McCarthy, H. Teplitz, C. Scarlata, B. Siana, A. Henry, J. Colbert, N. R. Ross, C. Bridge, A. J. Bunker, A. Dressler, R. A. E. Fosbury, C. martin, H. Shim
We present the WFC3 Infrared Spectroscopic Parallel (WISP) Survey. WISP is obtaining slitless, near-infrared grism spectroscopy of ~ 90 independent, high-latitude fields by observing in the pure parallel mode with Wide Field Camera-3 on the Hubble Space Telescope for a total of ~ 250 orbits. Spectra are obtained with the G102 (lambda=0.8-1.17 microns, R ~ 210) and G141 grisms (lambda=1.11-1.67 microns, R ~ 130), together with direct imaging in the J- and H-bands (F110W and F140W, respectively). In the present paper, we present the first results from 19 WISP fields, covering approximately 63 square arc minutes. For typical exposure times (~ 6400 sec in G102 and ~ 2700 sec in G141), we reach 5-sigma detection limits for emission lines of 5 x 10^(-17) ergs s^(-1) cm^(-2) for compact objects. Typical direct imaging 5sigma-limits are 26.8 and 25.0 magnitudes (AB) in F110W and F140W, respectively. Restricting ourselves to the lines measured with highest confidence, we present a list of 328 emission lines, in 229 objects, in a redshift range 0.3 < z < 3. The single-line emitters are likely to be a mix of Halpha and [OIII]5007,4959 A, with Halpha predominating. The overall surface density of high-confidence emission-line objects in our sample is approximately 4 per arcmin^(2).These first fields show high equivalent width sources, AGN, and post starburst galaxies. The median observed star formation rate of our Halpha selected sample is 4 Msol/year. At intermediate redshifts, we detect emission lines in galaxies as faint as H_140 ~ 25, or M_R < -19, and are sensitive to star formation rates down to less than 1 Msol/year. The slitless grisms on WFC3 provide a unique opportunity to study the spectral properties of galaxies much fainter than L* at the peak of the galaxy assembly epoch.
HST/WFC3 Near-Infrared spectroscopy of quenched galaxies at z~1.5 from the WISP Survey: Stellar population properties
我们将哈勃空间望远镜（HST）G102和G141近红外棱纹光谱与HST/WFC 3-UVIS、HST/WFC 3-IR和Spitzer/IRAC[3.6μm]测光相结合，组装了一个z~1.5的质量（log（M_star/M_sun）~ 11）淬灭星系样本。我们的41个星系的样本是最大的G102+G141近红外光谱淬灭源在这些红移。与局域宇宙相比，z~1.5淬灭星系在高质量范围内具有广泛的恒星星族性质。我们发现它们的SEDs很好地拟合了指数下降的SFH，和短的恒星形成时间尺度（τ<100 Myr）。淬火星系的年龄分布也很广，在1- 4 Gyr之间。在（u-r）_0-versus-mass空间中，淬火星系在给定质量下的静止坐标系颜色有很大的扩展。大多数猝灭星系都分布在z~1.5的红色序列（RS）中，但其中很大一部分（32%）的颜色更蓝。虽然有很大的扩展，我们发现RS上的淬灭星系的年龄中位数（3.1 Gyr）比RS外的淬灭星系（1.5 Gyr）要大。我们还表明，一个振兴的SED不能再现所观察到的堆叠光谱（蓝色）淬火星系关闭RS。我们推导出z~1.5时大质量星系在RS上所占比例的上限为<43%. We speculate that the young quenched galaxies OFF the RS are in a transition phase between vigorou…
A High Spatial Resolution Mid-Infrared Spectroscopic Study of the Nuclei and Star-Forming Regions in Luminous Infrared Galaxies
利用T-ReCS在Gemini South望远镜上对4个亮红外星系（LIRGs）的核和恒星形成区进行了高空间（衍射极限）分辨率（~0.3”）的中红外（MIR）光谱研究。我们调查的空间变化中看到的N-波段光谱的LIRGs的尺度上的~100 pc的功能，这使我们能够分离的AGN发射的恒星形成（SF）。我们比较我们的双子座T-ReCS核和积分光谱的LIRGs与斯皮策IRS。9.7um硅酸盐的吸收特征在LIRGs的核中比在周围区域中弱。这可能是由于要么cluerous或紧凑的环境，中央AGN或年轻，核星暴。我们发现[NeII]光度面密度与LIRG恒星形成区的Pa-α光度面密度紧密直接相关（斜率为1.00+-0.02）。尽管11.3 um PAH特征也显示了Pa-α的趋势，但这并不常见于所有区域。我们还发现[NeII] \Pa -α比率不依赖于Pa-α等效宽度（EW），即，的年龄的电离恒星星族，这表明，在这里探测的尺度上，[NeII]发射线是一个很好的示踪剂的SF活动的LIRGs。另一方面，11.3 um PAH \Pa -α比率随着Pa-α EW值的减小（年龄的增加）而增加，这表明11.3 um PAH特征也可以由比Pa-α发射更老的恒星激发。额外的高空间分辨率的观测是必不可少的调查，在统计的方式，在最小尺度上的本地LIRGs的恒星形成，并最终探测它们是否共享相同的物理性质的高z LIRG…
