| 1. |
- Akins, Hollis B., et al.
(author)
-
ALMA Reveals Extended Cool Gas and Hot Ionized Outflows in a Typical Star-forming Galaxy at Z=7.13
- 2022
-
In: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 934:1
-
Journal article (peer-reviewed)abstract
- We present spatially resolved morphological properties of [C II] 158 mu m, [O III] 88 mu m, dust, and rest-frame ultraviolet (UV) continuum emission for A1689-zD1, a strongly lensed, sub-L* galaxy at z = 7.13, by utilizing deep Atacama Large Millimeter/submillimeter Array (ALMA) and Hubble Space Telescope (HST) observations. While the [O III] line and UV continuum are compact, the [C II] line is extended up to a radius of r similar to 12 kpc. Using multi-band rest-frame far-infrared continuum data ranging from 52 to 400 mu m, we find an average dust temperature and emissivity index of Tdust=41-14+17 beta=1.7-0.7+1.1 6 galaxies.
|
|
| 2. |
- Manning, Sinclaire M., et al.
(author)
-
Characterization of Two 2 mm detected Optically Obscured Dusty Star-forming Galaxies
- 2022
-
In: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 925:1
-
Journal article (peer-reviewed)abstract
- The 2 mm Mapping Obscuration to Reionization with ALMA (MORA) Survey was designed to detect high-redshift (z greater than or similar to 4), massive, dusty star-forming galaxies (DSFGs). Here we present two likely high-redshift sources, identified in the survey, whose physical characteristics are consistent with a class of optical/near-infrared (OIR)-invisible DSFGs found elsewhere in the literature. We first perform a rigorous analysis of all available photometric data to fit spectral energy distributions and estimate redshifts before deriving physical properties based on our findings. Our results suggest the two galaxies, called MORA-5 and MORA-9, represent two extremes of the "OIR-dark" class of DSFGs. MORA-5 (z(phot) = 4.3(-1.3)(+1.5)) is a significantly more active starburst with a star formation rate (SFR) of 830(-190)(+340) M-circle dot yr(-1) compared to MORA-9 (z(phot) = 4.3(-1.0)(+1.3)), whose SFR is a modest 200(-60)(+250) M-circle dot yr(-1). Based on the stellar masses (M-star approximate to 10(10-11) M-circle dot), space density (n similar to (5 +/- 2) x 10(-6) Mpc(-3), which incorporates two other spectroscopically confirmed OIR-dark DSFGs in the MORA sample at z = 4.6 and z = 5.9), and gas depletion timescales (<1 Gyr) of these sources, we find evidence supporting the theory that OIR-dark DSFGs are the progenitors of recently discovered 3 < z < 4 massive quiescent galaxies.
|
|
| 3. |
- Welch, Brian, et al.
(author)
-
JWST Imaging of Earendel, the Extremely Magnified Star at Redshift z=6.2
- 2022
-
In: Astrophysical Journal Letters. - : Institute of Physics (IOP). - 2041-8205 .- 2041-8213. ; 940
-
Journal article (peer-reviewed)abstract
- The gravitationally lensed star WHL 0137-LS, nicknamed Earendel, was identified with a photometric redshift z (phot) = 6.2 +/- 0.1 based on images taken with the Hubble Space Telescope. Here we present James Webb Space Telescope (JWST) Near Infrared Camera images of Earendel in eight filters spanning 0.8-5.0 mu m. In these higher-resolution images, Earendel remains a single unresolved point source on the lensing critical curve, increasing the lower limit on the lensing magnification to mu > 4000 and restricting the source plane radius further to r < 0.02 pc, or similar to 4000 au. These new observations strengthen the conclusion that Earendel is best explained by an individual star or multiple star system and support the previous photometric redshift estimate. Fitting grids of stellar spectra to our photometry yields a stellar temperature of T (eff) similar to 13,000-16,000 K, assuming the light is dominated by a single star. The delensed bolometric luminosity in this case ranges from log(L)=5.8 L-theta, which is in the range where one expects luminous blue variable stars. Follow-up observations, including JWST NIRSpec scheduled for late 2022, are needed to further unravel the nature of this object, which presents a unique opportunity to study massive stars in the first billion years of the universe.
|
|
