Using member galaxy luminosities as halo mass proxies of galaxy groups

Reliable halo mass estimation for a given galaxy system plays an important role both in cosmology and galaxy formation studies. Here we set out to find the way that can improve the halo mass estimation for those galaxy systems with limited brightest member galaxies been observed. Using four mock galaxy samples constructed from semi-analytical formation models, the subhalo abundance matching method and the conditional luminosity functions, respectively, we find that the luminosity gap between the brightest and the subsequent brightest member galaxies in a halo (group) can be used to significantly reduce the scatter in the halo mass estimation based on the luminosity of the brightest galaxy alone. Tests show that these corrections can significantly reduce the scatter in the halo mass estimations by $\sim 50\%$ to $\sim 70\%$ in massive halos depending on which member galaxies are considered. Comparing to the traditional ranking method, we find that this method works better for groups with less than five members, or in observations with very bright magnitude cut.Comment: ApJ accepte

Strong-Weak Integrated Semi-supervision for Unsupervised Single and Multi Target Domain Adaptation

Unsupervised domain adaptation (UDA) focuses on transferring knowledge learned in the labeled source domain to the unlabeled target domain. Despite significant progress that has been achieved in single-target domain adaptation for image classification in recent years, the extension from single-target to multi-target domain adaptation is still a largely unexplored problem area. In general, unsupervised domain adaptation faces a major challenge when attempting to learn reliable information from a single unlabeled target domain. Increasing the number of unlabeled target domains further exacerbate the problem rather significantly. In this paper, we propose a novel strong-weak integrated semi-supervision (SWISS) learning strategy for image classification using unsupervised domain adaptation that works well for both single-target and multi-target scenarios. Under the proposed SWISS-UDA framework, a strong representative set with high confidence but low diversity target domain samples and a weak representative set with low confidence but high diversity target domain samples are updated constantly during the training process. Both sets are fused to generate an augmented strong-weak training batch with pseudo-labels to train the network during every iteration. The extension from single-target to multi-target domain adaptation is accomplished by exploring the class-wise distance relationship between domains and replacing the strong representative set with much stronger samples from peer domains via peer scaffolding. Moreover, a novel adversarial logit loss is proposed to reduce the intra-class divergence between source and target domains, which is back-propagated adversarially with a gradient reverse layer between the classifier and the rest of the network. Experimental results based on three benchmarks, Office-31, Office-Home, and DomainNet, show the effectiveness of the proposed SWISS framework

Constraining the Star Formation Histories in Dark Matter Halos: I. Central Galaxies

Using the self-consistent modeling of the conditional stellar mass functions across cosmic time by Yang et al. (2012), we make model predictions for the star formation histories (SFHs) of {\it central} galaxies in halos of different masses. The model requires the following two key ingredients: (i) mass assembly histories of central and satellite galaxies, and (ii) local observational constraints of the star formation rates of central galaxies as function of halo mass. We obtain a universal fitting formula that describes the (median) SFH of central galaxies as function of halo mass, galaxy stellar mass and redshift. We use this model to make predictions for various aspects of the star formation rates of central galaxies across cosmic time. Our main findings are the following. (1) The specific star formation rate (SSFR) at high $z$ increases rapidly with increasing redshift [$\propto (1+z)^{2.5}$] for halos of a given mass and only slowly with halo mass ($\propto M_h^{0.12}$) at a given $z$, in almost perfect agreement with the specific mass accretion rate of dark matter halos. (2) The ratio between the star formation rate (SFR) in the main-branch progenitor and the final stellar mass of a galaxy peaks roughly at a constant value, $\sim 10^{-9.3} h^2 {\rm yr}^{-1}$, independent of halo mass or the final stellar mass of the galaxy. However, the redshift at which the SFR peaks increases rapidly with halo mass. (3) More than half of the stars in the present-day Universe were formed in halos with 10^{11.1}\msunh < M_h < 10^{12.3}\msunh in the redshift range $0.4 < z < 1.9$. (4) ... [abridged]Comment: 15 figures, 22 pages, Accepted for publication in Ap

The Incomplete Conditional Stellar Mass Function: Unveiling the Stellar Mass Functions of Galaxies at 0.1 < Z < 0.8 from BOSS Observations

We propose a novel method to constrain the missing fraction of galaxies using galaxy clustering measurements in the galaxy conditional stellar mass function (CSMF) framework, which is applicable to surveys that suffer significantly from sample selection effects. The clustering measurements, which are not sensitive to the random sampling (missing fraction) of galaxies, are widely used to constrain the stellar-halo mass relation (SHMR). By incorporating a missing fraction (incompleteness) component into the CSMF model (ICSMF), we use the incomplete stellar mass function and galaxy clustering to simultaneously constrain the missing fractions and the SHMRs. Tests based on mock galaxy catalogs with a few typical missing fraction models show that this method can accurately recover the missing fraction and the galaxy SHMR, and hence provides us reliable measurements of the galaxy stellar mass functions. We then apply it to the Baryon Oscillation Spectroscopic Survey (BOSS) over the redshift range of 0.110^{11}M_\odot$. We find the sample completeness for BOSS is over 80to about 30accurate measurements of the stellar mass functions for galaxies with$10^{11}M_\odot<M_*<10^{12}M_\odot$, as well as the SHMRs, over the redshift range 0.1<z<0.8 in this largest galaxy redshift survey.Comment: 18 pages, 12 figures. Accepted for publication in Ap

Efficacy of the combination of Tenghuangjiangu tablets, alfacalcidol capsules and caltrate D3 tablets in osteoporotic vertebral compression fracture, and their effects on bone metabolic indices

Purpose: To investigate the efficacy of the combination of Tenghuangjiangu tablets, Alfacalcidol capsules and Caltrate D3 tablets in osteoporotic vertebral compression fracture (OVCF) and their effects on bone metabolic indices. Methods: Ninety-six patients with OVCF were randomly categorized into study group (SG) and control group (CG). Patients in the CG orally took Caltrate D3 tablets, while those in the SG were given Tenghuangjiangu tablets and Alfacalcidol capsules in addition to caltrate D3 tablets. The Bone mineral density (BMD) values and the treatment efficacy were compared. The levels of bone metabolism markers (PINP, β-CTX, BGP, NBAP), CT and PTH were determined using electrochemiluminescence immunoassay, while Ca2+ levels were assessed using liquid level detection. The incidence of adverse reactions (re-fracture, gastrointestinal reaction, hypotension and abnormal coagulation function) were compared. Results: Treatment efficacy in the SG was 91.67 %, which was significantly higher than that in the CG (81.25 %; p &lt; 0.05). Before treatment, the two groups showed no significant differences in BMD, PINP, β-CTX, BGP, NBAP, Ca2+, CT, and PTH levels (p &gt; 0.05). After treatment, the SG exhibited significantly higher BMD, PINP, BGP, NBAP, Ca2+ and CT levels, and showed lower β-CTX and PTH levels than the CG (p &lt; 0.05). The SG exhibited a significantly lower incidence rate of adverse reactions than that the CG (p &lt; 0.05). Conclusion: The combination of Tenghuangjiangu tablets, Alfacalcidol capsules, and Caltrate D3 tablets, improves bone metabolic indices, bone density and treatment efficacy while reducing the incidence rate of adverse reactions