66 research outputs found
Far-infrared And Nebular Star-formation Rates Of Dusty Star Forming Galaxies From Herschel And 3d-hst At Z~1
We present results of a multi-band Spectral Energy Distribution (SED) and
nebular emission line analysis of a sample of 1147 spectroscopically identified
dusty star-forming galaxies at 0.49 < z < 2.24 from Herschel/SPIRE and HST/WFC3
grism observations in the five CANDELS fields: AEGIS, GOODS-N, GOODS-S, COSMOS,
and UDS. We use the spectroscopic redshifts measured from nebular lines to
construct the SEDs of galaxies from the optical to the infrared using HST and
Herschel photometry. We further utilize the 3D-HST grism Ha line flux
measurements to measure the nebular star-formation rates after correcting for
attenuation. We compare this with direct observations of the SFR measurements
in the far-infrared from Herschel. Observation of the infrared excess (IRX) in
this sample as a function of the UV spectral slope reveals that these DSFGs
deviate toward bluer colors, thus sitting well above the expected relation for
normal star-forming galaxies. The high-z dusty galaxies have a stellar mass
distribution that is skewed towards larger masses, with . However this population has star-formation rates consistent
with the most massive tail of the main sequence, showing that these are both
the most massive and the most star-forming galaxies during the peak epoch of
formation.Comment: 9 pages, 7 figures, ApJ submitte
Spectroscopic study of star-forming galaxies in filaments and the field at 0.5:evidence for environmental dependence of electron density
We study the physical properties of a spectroscopic sample of 28 star-forming galaxies in a large filamentary structure in the COSMOS field at 0.53, with spectroscopic data taken with the Keck/DEIMOS spectrograph, and compare them with a control sample of 30 field galaxies. We spectroscopically confirm the presence of a large galaxy filament ( 8 Mpc), along which five confirmed X-ray groups exist. We show that within the uncertainties, the ionization parameter, equivalent width (EW), EW versus specific star-formation rate (sSFR) relation, EW versus stellar mass relation, line-of-sight velocity dispersion, dynamical mass, and stellar-to-dynamical mass ratio are similar for filament and field star-forming galaxies. However, we show that on average, filament star-forming galaxies are more metal-enriched ( 0.10.15 dex), possibly due to the inflow of the already enriched intrafilamentary gas into filament galaxies. Moreover, we show that electron densities are significantly lower (a factor of 17) in filament star-forming systems compared to those in the field, possibly because of a longer star-formation timescale for filament star-forming galaxies. Our results highlight the potential pre-processing role of galaxy filaments and intermediate-density environments on the evolution of galaxies, which has been highly underestimated
Kpc-scale Properties of Emission-line Galaxies
We perform a detailed study of the resolved properties of emission-line
galaxies at kpc-scale to investigate how small-scale and global properties of
galaxies are related. 119 galaxies with high-resolution Keck/DEIMOS spectra are
selected to cover a wide range in morphologies over the redshift range
0.2<z<1.3. Using the HST/ACS and HST/WFC3 imaging data taken as a part of the
CANDELS project, for each galaxy we perform SED fitting per resolution element,
producing resolved rest-frame U-V color, stellar mass, star formation rate, age
and extinction maps. We develop a technique to identify blue and red "regions"
within individual galaxies, using their rest-frame color maps. As expected, for
any given galaxy, the red regions are found to have higher stellar mass surface
densities and older ages compared to the blue regions. Furthermore, we quantify
the spatial distribution of red and blue regions with respect to both redshift
and stellar mass, finding that the stronger concentration of red regions toward
the centers of galaxies is not a significant function of either redshift or
stellar mass. We find that the "main sequence" of star forming galaxies exists
among both red and blue regions inside galaxies, with the median of blue
regions forming a tighter relation with a slope of 1.1+/-0.1 and a scatter of
~0.2 dex compared to red regions with a slope of 1.3+/-0.1 and a scatter of
~0.6 dex. The blue regions show higher specific Star Formation Rates (sSFR)
than their red counterparts with the sSFR decreasing since z~1, driver
primarily by the stellar mass surface densities rather than the SFRs at a giver
resolution element.Comment: 17 pages, 17 figures, Submitted to the Ap
RoboEXP: Action-Conditioned Scene Graph via Interactive Exploration for Robotic Manipulation
Robots need to explore their surroundings to adapt to and tackle tasks in
unknown environments. Prior work has proposed building scene graphs of the
environment but typically assumes that the environment is static, omitting
regions that require active interactions. This severely limits their ability to
handle more complex tasks in household and office environments: before setting
up a table, robots must explore drawers and cabinets to locate all utensils and
condiments. In this work, we introduce the novel task of interactive scene
exploration, wherein robots autonomously explore environments and produce an
action-conditioned scene graph (ACSG) that captures the structure of the
underlying environment. The ACSG accounts for both low-level information, such
as geometry and semantics, and high-level information, such as the
action-conditioned relationships between different entities in the scene. To
this end, we present the Robotic Exploration (RoboEXP) system, which
incorporates the Large Multimodal Model (LMM) and an explicit memory design to
enhance our system's capabilities. The robot reasons about what and how to
explore an object, accumulating new information through the interaction process
and incrementally constructing the ACSG. We apply our system across various
real-world settings in a zero-shot manner, demonstrating its effectiveness in
exploring and modeling environments it has never seen before. Leveraging the
constructed ACSG, we illustrate the effectiveness and efficiency of our RoboEXP
system in facilitating a wide range of real-world manipulation tasks involving
rigid, articulated objects, nested objects like Matryoshka dolls, and
deformable objects like cloth.Comment: Project Page: https://jianghanxiao.github.io/roboexp-web
- …