62 research outputs found
On the anomalous dynamics of capillary rise in porous media
The anomalous dynamics of capillary rise in a porous medium discovered
experimentally more than a decade ago (Delker et al., Phys. Rev. Lett. 76
(1996) 2902) is described. The developed theory is based on considering the
principal modes of motion of the menisci that collectively form the wetting
front on the Darcy scale. These modes, which include (i) dynamic wetting mode,
(ii) threshold mode and (iii) interface de-pinning process, are incorporated
into the boundary conditions for the bulk equations formulated in the regular
framework of continuum mechanics of porous media, thus allowing one to consider
a general case of three-dimensional flows. The developed theory makes it
possible to describe all regimes observed in the experiment, with the time
spanning more than four orders of magnitude, and highlights the dominant
physical mechanisms at different stages of the process
Revisiting the Color-Color Selection: Submillimeter and AGN Properties of NUV-r-J Selected Quiescent Galaxies
We examine the robustness of the color-color selection of quiescent galaxies
(QGs) against contamination of dusty star-forming galaxies using the latest
submillimeter data. We selected 18,304 QG candidates out to 3 using the
commonly adopted selection based on the high-quality multi-wavelength
COSMOS2015 catalog. Using extremely deep 450 and 850 m catalogs from the
latest JCMT SCUBA-2 Large Programs, S2COSMOS, and STUDIES, as well as ALMA
submillimeter, VLA 3 GHz, and MIPS 24 m catalogs, we identified
luminous dusty star-forming galaxies among the QG candidates. We also conducted
stacking analyses in the SCUBA-2 450 and 850 m images to look for
less-luminous dusty galaxies among the QG candidates. By cross-matching to the
24 m and 3 GHz data, we were able to identify a sub-group of
"IR-radio-bright" QGs who possess a strong 450 and 850 m stacking signal.
The potential contamination of these luminous and less-luminous dusty galaxies
accounts for approximately 10% of the color-selected QG candidates. In
addition, there exists a spatial correlation between the luminous star-forming
galaxies and the QGs at a kpc scale. Finally, we found a high QG
fraction among radio AGNs at 1.5. Our data show a strong correlation
between QGs and radio AGNs, which may suggest a connection between the
quenching process and the radio-mode AGN feedback.Comment: This paper is accepted for publication on Ap
SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES). II. Structural Properties and Near-infrared Morphologies of Faint Submillimeter Galaxies
We present structural parameters and morphological properties of faint 450 μm selected submillimeter galaxies (SMGs) from the JCMT Large Program, STUDIES, in the COSMOS-CANDELS region. Their properties are compared to an 850 μm selected and a matched star-forming samples. We investigate stellar structures of 169 faint 450 μm sources (S 450 = 2.8–29.6 mJy; S/N > 4) at z 2 mJy) and more extended than the star-forming galaxies in the same redshift range. For the stellar mass and SFR-matched sample at z sime 1 and z sime 2, the size differences are marginal between faint SMGs and the matched galaxies. Moreover, faint SMGs have similar Sérsic indices and projected axis ratios as star-forming galaxies with the same stellar mass and SFR. Both SMGs and the matched galaxies show high fractions (~70%) of disturbed features at z sime 2, and the fractions depend on the SFRs. These suggest that their star formation activity is related to galaxy merging and the stellar structures of SMGs are similar to those of star-forming galaxies. We show that the depths of submillimeter surveys are approaching the lower luminosity end of star-forming galaxies, allowing us to detect galaxies on the main sequence
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