Cloud fragmentation into dense cores is a critical step in the process of star formation. A number of recent observations show that it is connected to the filamentary structure of the gas, but the processes responsible for core formation remain mysterious. We studied the kinematics and spatial distribution of the dense gas in the L1495/B213 filamentary region of the Taurus molecular cloud with the goal of understanding the mechanism of core formation. We mapped the densest regions of L1495/B213 in N2H+(1–0) and C18O(2–1) with the IRAM 30 m telescope, and complemented these data with archival dust-continuum observations from the Herschel Space Observatory. The dense cores in L1495/B213 are significantly clustered in linear chain-like groups about 0.5 pc long. The internal motions in these chains are mostly subsonic and the velocity is continuous, indicating that turbulence dissipation in the cloud has occurred at the scale of the chains and not at the smaller scale of the individual cores. The chains also present an approximately constant abundance of N2H+ and radial intensity profiles that can be modeled with a density law that follows a softened power law. A simple analysis of the spacing between the cores using an isothermal cylinder model indicates that the cores have likely formed by gravitational fragmentation of velocity-coherent filaments. Combining our analysis of the cores with our previous study of the large-scale C18O emission from the cloud, we propose a two-step scenario of core formation in L1495/B213. In this scenario, named “fray and fragment”, L1495/B213 originated from the supersonic collision of two flows. The collision produced a network of intertwined subsonic filaments or fibers (fray step). Some of these fibers accumulated enough mass to become gravitationally unstable and fragment into chains of closely-spaced cores.

Most of the gravitating matter in the universe is 'dark'. Galaxies are grouped into clusters and super-clusters and it is important to know whether the dark matter is distributed the same way. There are many reasons for suspecting that baryons may have condensed more efficiently into galaxies in regions of above-average density. The overall matter distribution would then be smoother than one would infer on the assumption that galaxies trace mass. The data are incompatible with the hypothesis that the Universe has the critical density unless galaxy formation was biased in this sense.

We present a comprehensive study of star-forming (SF) galaxies in the Hubble Space Telescope (HST) Frontier Field recent cluster merger A2744 (z = 0.308). Wide-field, ultraviolet-infrared (UV-IR) imaging enables a direct constraint of the total star formation rate (SFR) for 53 cluster galaxies, with SFRUV+IR = 343 ± 10 M⊙ yr-1. Within the central 4 arcmin (1.1 Mpc) radius, the integrated SFR is complete, yielding a total SFRUV+IR = 201 ± 9 M⊙ yr-1. Focusing on obscured star formation, this core region exhibits a total SFRIR = 138 ± 8 M⊙ yr-1, a mass-normalized SFRIR of ΣSFR = 11.2 ± 0.7 M⊙ yr-1 per 1014 M⊙ and a fraction of IR-detected SF galaxies f_SF = 0.080^{+0.010}_{-0.037}. Overall, the cluster population at z ˜ 0.3 exhibits significant intrinsic scatter in IR properties (total SFRIR, Tdust distribution) apparently unrelated to the dynamical state: A2744 is noticeably different to the merging Bullet cluster, but similar to several relaxed clusters. However, in A2744 we identify a trail of SF sources including jellyfish galaxies with substantial unobscured SF due to extreme stripping (SFRUV/SFRIR up to 3.3). The orientation of the trail, and of material stripped from constituent galaxies, indicates that the passing shock front of the cluster merger was the trigger. Constraints on star formation from both IR and UV are crucial for understanding galaxy evolution within the densest environments.

To measure precise of polarization need a strong polarized absolute calibrator on the sky to accurately set polarization angle and the cross-polarization leakage. As the most intense polarized source in the microwave sky at angular scales of few arcminutes, the Crab nebula will be used for this purpose. so, we processed the Stokes I, Q, and U maps in order to compute the polarization angle and linear polarization fraction of the Crab nebula at 90 GHz by IRAM 30m telescope.

We present the results of optical (R band) photometric and polarimetric monitoring and Very Long Baseline Array (VLBA) imaging of the blazar S5 0716+714 along with Fermi γ -ray data during a multi-waveband outburst in 2011 October. We analyze total and polarized intensity images of the blazar obtained with the VLBA at 43 GHz during and after the outburst. Monotonic rotation of the linear polarization vector at a rate of ?50? per night coincided with a sharp maximum in γ -ray and optical flux. At the same time, within the uncertainties, a new superluminal knot appeared with an apparent speed of 21 ± 2c. The general multi-frequency behavior of the outburst can be explained within the framework of a shock wave propagating along a helical path in the blazar’s jet.

Sgr A*, which is the strong radio emission region at the center of our galaxy, has largely affected by the scattering medium along with our line of sight. The scattering medium causes a angular broadening of the measured size of Sgr A* by refracting the emission. One of our goal is to resolve the very inner region of the supermassive black hole, so measuring the size and structure of Sgr A* is quiet important. Therefore, constraining the properties of scattering medium is one of the main goal for Sgr A* study. Here, two researches suggested the location of the scattering medium by studying an ambient magnetar, J1745-2900. We will see each result and the way of their study.

An analysis of very short-arc orbit determination for low-Earth objects using sparse optical and laser tracking data

Microlensing Surveys for Exoplanets

Detection of planetary companions around K giants HD 40956, HD 111591, and HD 113996

Source and seed populations for relativistic electrons: Their roles in radiation belt changes

Geometrical Relationship Between Interplanetary Flux Ropes and Their Solar Sources

The Grad-Shafranov Equations of Axisymmetric, Nonstationary Models of the Central Engine in an Active Galactic Nucleus

DISCOVERY OF SUBSTRUCTURE IN THE SCATTER-BROADENED IMAGE OF SGR A*

The nature of the UV halo around spiral galaxies with extraplanar dust

Characteristics and source of the electron density irregularities in the Earth's ionosphere

IGRINS NEAR-IR HIGH-RESOLUTION SPECTROSCOPY OF MULTIPLE JETS AROUND LkHa 234

A standard law for the equatorward drift of the sunspot zones

Local orbital debris flux study in the geostationary ring

Van Allen Probes observations linking radiation belt electrons to chorus waves during 2014 multiple storms

BOSS: A Ruler to Measure Them All

Theoretical Models of Dark Energy

Orion KL Explosive Outflow

The Herschel Fornax Cluster Survey: FIR properties of optically selected Fornax cluster galaxies

Comparison of Helicity Signs in Interplanetary CMEs and Their Solar Regions

An X-ray Flare from 47 CAS

ALMA : In search of out Cosmic Origins

G2 cloud encounter on SgrA*