Observations of IRAS F10214+4724 at the Nobeyama millimeter array

F10214+4724 is an IRAS source at z=2.286 with L(sub FIR) approximately 10(exp 14) solar luminosity. The CO(3-2) emission was detected at the NRAO 12-m telescope, and its molecular gas mass was estimated to be (1-3)x10(exp 11) solar mass. This object is unique and important because it is the first high-z object from which molecular line emission is detected and it enables us to investigate molecular gas content, star forming material, at an early stage of galactic evolution. If IRAS F10214+4724 is a primeval galaxy at the formation process, it is possible the gas has not been collapsed yet to the galactic scale. On the other hand, it is also possible IRAS F10214+4724 is a merging or interacting system like the most of ultra-luminous infrared galaxies. However, since the first detection was made with a medium size single-dish telescope, the precise position, extent, and distribution of the molecular gas had not been determined. The aim of our aperture synthesis observations is therefore to determine position and distribution of molecular gas

Optimal Alignment Sensing of a Readout Mode Cleaner Cavity

Critically coupled resonant optical cavities are often used as mode cleaners in optical systems to improve the signal to noise ratio (SNR) of a signal that is encoded as an amplitude modulation of a laser beam. Achieving the best SNR requires maintaining the alignment of the mode cleaner relative to the laser beam on which the signal is encoded. An automatic alignment system which is primarily sensitive to the carrier field component of the beam will not, in general, provide optimal SNR. We present an approach that modifies traditional dither alignment sensing by applying a large amplitude modulation on the signal field, thereby producing error signals that are sensitive to the signal sideband field alignment. When used in conjunction with alignment actuators, this approach can improve the detected SNR; we demonstrate a factor of 3 improvement in the SNR of a kilometer-scale detector of the Laser Interferometer Gravitational-wave Observatory. This approach can be generalized to other types of alignment sensors

Random global coupling induces synchronization and nontrivial collective behavior in networks of chaotic maps

The phenomena of synchronization and nontrivial collective behavior are studied in a model of coupled chaotic maps with random global coupling. The mean field of the system is coupled to a fraction of elements randomly chosen at any given time. It is shown that the reinjection of the mean field to a fraction of randomly selected elements can induce synchronization and nontrivial collective behavior in the system. The regions where these collective states emerge on the space of parameters of the system are calculated.Comment: 2 pages, 2 figs, accepted in The European Physical Journa

High Angular Resolution, Sensitive CS J=2-1 and J=3-2 Imaging of the Protostar L1551 NE: Evidence for Outflow-Triggered Star Formation ?

High angular resolution and sensitive aperture synthesis observations of CS ($J=2-1$) and CS ($J=3-2$) emissions toward L1551 NE, the second brightest protostar in the Taurus Molecular Cloud, made with the Nobeyama Millimeter Array are presented. L1551 NE is categorized as a class 0 object deeply embedded in the red-shifted outflow lobe of L1551 IRS 5. Previous studies of the L1551 NE region in CS emission revealed the presence of shell-like components open toward L1551 IRS 5, which seem to trace low-velocity shocks in the swept-up shell driven by the outflow from L1551 IRS 5. In this study, significant CS emission around L1551 NE was detected at the eastern tip of the swept-up shell from $V_{\rm{lsr}}$ = 5.3 km s$^{-1}$ to 10.1 km s$^{-1}$, and the total mass of the dense gas is estimated to be 0.18 $\pm$ 0.02 $M_\odot$. Additionally, the following new structures were successfully revealed: a compact disklike component with a size of $\approx$ 1000 AU just at L1551 NE, an arc-shaped structure around L1551 NE, open toward L1551 NE, with a size of $\sim 5000$ AU, i.e., a bow shock, and a distinct velocity gradient of the dense gas, i.e., deceleration along the outflow axis of L1551 IRS 5. These features suggest that the CS emission traces the post-shocked region where the dense gas associated with L1551 NE and the swept-up shell of the outflow from L1551 IRS 5 interact. Since the age of L1551 NE is comparable to the timescale of the interaction, it is plausible that the formation of L1551 NE was induced by the outflow impact. The compact structure of L1551 NE with a tiny envelope was also revealed, suggesting that the outer envelope of L1551 NE has been blown off by the outflow from L1551 IRS 5.Comment: 29 pages, 12 figures, Accepted for Publication in the Astrophysical Journa

Millimeter- and Submillimeter-Wave Observations of the OMC-2/3 Region. II. Observational Evidence for Outflow-Triggered Star Formation in the OMC-2 FIR 3/4 Region

We have carried out the observations of the OMC-2 FIR 3/4 region with the NMA and ASTE in the H$^{13}$CO$^{+}$ (1--0), $^{12}$CO (3--2, 1--0), SiO ($v$=0, $J$=2--1), CS (2--1), and CH$_3$OH ($J_K$=7$_K$--6$_K$) lines and in the 3.3 mm continuum emission. Our NMA observations in the H$^{13}$CO$^{+}$ emission have revealed 0.07 pc-scale dense gas associated with FIR 4. The $^{12}$CO (3--2,1--0) emission shows high-velocity blue and red shifted components at the both north-east and south-west of FIR 3, suggesting a molecular outflow nearly along the plane of the sky driven by FIR 3. The SiO and the CH$_{3}$OH emission are detected around the interface between the outflow and the dense gas. Furthermore, the $^{12}$CO (1--0) emission shows an L-shaped structure in the P-V diagram. These results imply presence of the shock due to the interaction between the molecular outflow driven by FIR 3 and the dense gas associated with FIR 4. Moreover, our high angular-resolution observations of FIR 4 in the 3.3 mm continuum emission have first found that FIR 4 consists of eleven dusty cores. The separation among these cores is on the same order of the Jeans length, suggesting that the fragmentation into these cores has been caused by the gravitational instability. The time scale of the fragmentation is similar to the time scale of the interaction between the molecular outflow and the dense gas. We suggest that the interaction between the molecular outflow from FIR 3 and the dense gas associated with FIR 4 triggered the fragmentation into these dusty cores, and hence the next generation the cluster formation.Comment: 13 pages, 9 figures. Accepted by Ap