ﻻ يوجد ملخص باللغة العربية
We present the rest-frame optical sizes of massive quiescent galaxies (QGs) at $zsim4$ measured at $K$-band with the Infrared Camera and Spectrograph (IRCS) and AO188 on the Subaru telescope. Based on a deep multi-wavelength catalog in the Subaru XMM-Newton Deep Survey Field (SXDS), covering a wide wavelength range from the $u$-band to the IRAC $8.0mu m$ over 0.7 deg$^2$, we evaluate photometric redshift to identify massive ($M_{star}sim10^{11} M_odot$) galaxies with suppressed star formation. These galaxies show a prominent 4000$rm AA$ break feature at $zsim4$, suggestive of an evolved stellar population. We then conduct follow-up $K$-band imaging with adaptive optics for the five brightest galaxies ($K_{AB,total}=22.5sim23.4$). Compared to lower redshift ones, QGs at $zsim4$ have smaller physical sizes of effective radii $r_{eff}=0.2$ to $1.8$ kpc. The mean size measured by stacking the four brightest objects is $r_{eff}=0.7rm kpc$. This is the first measurement of the rest-frame optical sizes of QGs at $zsim4$. We evaluate the robustness of our size measurements using simulations and find that our size estimates are reasonably accurate with an expected systematic bias of $sim0.2$ kpc. If we account for the stellar mass evolution, massive QGs at $zsim4$ are likely to evolve into the most massive galaxies today. We find their size evolution with cosmic time in a form of $log(r_e/{rm kpc})= -0.44+1.77 log(t/rm Gyr)$. Their size growth is proportional to the square of stellar mass, indicating the size-stellar mass growth driven by minor dry mergers.
Despite the existence of well-defined relationships between cold gas and star formation, there is evidence that some galaxies contain large amounts of HI that do not form stars efficiently. By systematically assessing the link between HI and star for
We compare the rest-frame ultraviolet and rest-frame optical morphologies of 2 < z < 3 star-forming galaxies in the GOODS-S field using Hubble Space Telescope WFC3 and ACS images from the CANDELS, GOODS, and ERS programs. We show that the distributio
We present the average rest-frame spectrum of high-redshift dusty, star-forming galaxies from 250-770GHz. This spectrum was constructed by stacking ALMA 3mm spectra of 22 such sources discovered by the South Pole Telescope and spanning z=2.0-5.7. In
We use the high angular resolution in the near-infrared of the WFC3 on HST to determine YHVz color-color selection criteria to identify and characterize 1.5<z<3.5 galaxies in the HUDF09 and ERS (GOODS-South) fields. The WFC3 NIR images reveal galaxie
We study the rest-frame ultra-violet sizes of massive (~0.8 x 10^11 M_Sun) galaxies at 3.4<z<4.2, selected from the FourStar Galaxy Evolution Survey (ZFOURGE), by fitting single Sersic profiles to HST/WFC3/F160W images from the Cosmic Assembly Near-I