Discovery of Extraplanar H i Clouds and a H i Tail in the M101 Galaxy Group with FAST

Abstract We present a new high-sensitivity H i observation toward nearby spiral galaxy M101 and its adjacent 2° × 2° region using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). From the observation, we detect a more extended and asymmetric H i disk around M101. While the H i velocity field within the M101's optical disk region is regular, indicating that the relatively strong disturbance occurs in its outer disk. Moreover, we identify three new H i clouds located on the southern edge of the M101's H i disk. The masses of the three H i clouds are 1.3 × 107 M ⊙, 2.4 × 107 M ⊙, and 2.0 × 107 M ⊙, respectively. The H i clouds similar to dwarf companion NGC 5477 rotate with the H i disk of M101. Unlike NGC 5477, they have no optical counterparts. Furthermore, we detect a new H i tail in the extended H i disk of M101. The H i tail detected gives reliable evidence for M101 interaction with the dwarf companion NGC 5474. We argue that the extraplanar gas (three H i clouds) and the H i tail detected in the M101's disk may originate from a minor interaction with NGC 5474.

Download Full-text

HI Study of the NGC 6744 System

Publications of the Astronomical Society of Australia ◽

10.1071/as99084 ◽

1999 ◽

Vol 16 (1) ◽

pp. 84-88 ◽

Cited By ~ 7

Author(s):

Stuart D. Ryder ◽

Wilfred Walsh ◽

David Malin

Keyword(s):

Velocity Field ◽

Spiral Galaxy ◽

Neutral Hydrogen ◽

Optical Disk ◽

Mass Model ◽

Spiral Arms ◽

Preliminary Results ◽

Heliocentric Velocity ◽

Compact Array

AbstractWe present the preliminary results of our 5-configuration, 20-pointing mosaic with the Australia Telescope Compact Array of the neutral hydrogen in the nearby spiral galaxy NGC 6744. The bulk of the HI resides in a ‘ring’ underlying the outer optical disk, with 2 HI spiral arms extending further out to almost 1·5 optical radii. The velocity field is fairly regular, apart from evidence for streaming motions along the HI arms, and the influence of the companion IB(s)m galaxy NGC 6744A. We associate a cloud of HI at a heliocentric velocity of 846 km s−1 with another companion object, ESO 104–g44. Our attempts to construct a mass model for NGC 6744 suffer from poor resolution in the inner disk, and the uncertainty in the total HI flux of NGC 6744. We anticipate that HIPASS observations will be crucial in resolving the latter issue.

Download Full-text

Yebes 40 m radio telescope and the broad band Nanocosmos receivers at 7 mm and 3 mm for line surveys

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038701 ◽

2021 ◽

Vol 645 ◽

pp. A37

Author(s):

F. Tercero ◽

J. A. López-Pérez ◽

J. D. Gallego ◽

F. Beltrán ◽

O. García ◽

...

Keyword(s):

Radio Telescope ◽

Signal To Noise Ratio ◽

Broad Band ◽

High Sensitivity ◽

Lower Sensitivity ◽

Molecular Chemistry ◽

Long Baseline ◽

New Instrumentation ◽

Frequency Coverage ◽

Technical Specifications

Context. Yebes 40 m radio telescope is the main and largest observing instrument at Yebes Observatory and is devoted to very long baseline interferometry (VLBI) and single-dish observations since 2010. It has been covering frequency bands between 2 GHz and 90 GHz in discontinuous and narrow windows in most cases in order to match the current needs of the European VLBI Network (EVN) and the Global Millimeter VLBI Array (GMVA). Aims. The Nanocosmos project, a European Union-funded synergy grant, has enabled an increase in the instantaneous frequency coverage of the Yebes 40 m radio telescope, making it possible to observe many molecular transitions with single tunings in single-dish mode. This reduces the observing time and maximises the output from the telescope. Methods. We present technical specifications of the recently installed 31.5−50 GHz (Q band) and 72−90.5 GHz (W band) receivers along with the main characteristics of the telescope at these frequency ranges. We observed IRC+10216, CRL 2688, and CRL 618, which harbour a rich molecular chemistry, to demonstrate the capabilities of the new instrumentation for spectral observations in single-dish mode. Results. Our results show the high sensitivity of the telescope in the Q band. The spectrum of IRC+10126 offers an unprecedented signal-to-noise ratio for this source in this band. On the other hand, the spectrum normalised by the continuum flux towards CRL 618 in the W band demonstrates that the 40 m radio telescope produces comparable results to those from the IRAM 30 m radio telescope, although with a lower sensitivity. The new receivers fulfil one of the main goals of Nanocosmos and open up the possibility to study the spectrum of different astrophysical media with unprecedented sensitivity.

Download Full-text

Strain effects of nuclear explosions in Nevada

Bulletin of the Seismological Society of America ◽

10.1785/bssa0610010055 ◽

1971 ◽

Vol 61 (1) ◽

pp. 55-64 ◽

Cited By ~ 3

Author(s):

Gary Boucher ◽

Stephen D. Malone ◽

E. Fred Homuth

Keyword(s):

Body Wave ◽

High Sensitivity ◽

Test Site ◽

Strain Effects ◽

Underground Nuclear Explosions ◽

Static Strain ◽

Nuclear Explosions ◽

Shot Point ◽

A Minor ◽

The University

abstract The University of Nevada's three-component quartz-rod strain meter installation at Round Mountain, Nevada (38°42.1′N, 117°04.6′W) has recorded a number of underground nuclear explosions at the Nevada Test Site, beginning with the megaton-sized JORUM event September 16 1969. Both that explosion and the larger HANDLEY event on March 26 1970 produced static strain offsets of a few parts in 109 at Round Mountain. These offsets did not decay within the first few hours after the explosions. In both cases, the strain offsets were in the sense of ground extension radial to the shot point, which is inconsistent with the assumption of a pure compressive source of strain. The strain-change ellipse for the HANDLEY event was found to have a major strain axis of 11 × 10−9 extensional, oriented N 34°W, and a minor axis of 7.4 × 10−9 compressional. A single-component strain meter at Mina, Nevada, (38°26.3′N, 118°9.3′W) was operated for the HANDLEY event, and recorded a strain offset of 2.6 × 10−9 in the direction N 74°E. Strain offsets at the time of the largest collapse events following HANDLEY were observed at Round Mountain. These offsets had the same sense on each component as those following the explosion itself. This is interpreted as support for the hypothesis that the strain changes are tectonic in origin, and the explosion initiates the strain release. Small offsets were observed for three smaller explosions out of a total of 13 studied. The relationship between body-wave magnitude mb and maximum dynamic strains at Round Mountain may be described empirically by the equation Log S = − 13.4 + 1.10 mb. Because of its high sensitivity and stability, the Round Mountain strain meter is capable of obtaining useful measurements of dynamic and static strain effects of intermediate- to large-sized explosions, at distances ranging from 160 to 200 km.

Download Full-text

2.1.3 Composition of Impact-Plasma measured by a HELIOS-Micrometeoroid-Detector

International Astronomical Union Colloquium ◽

10.1017/s0252921100051654 ◽

1976 ◽

Vol 31 ◽

pp. 164-164

Author(s):

B.-K. Dalmann ◽

E. Grün ◽

J. Kissel

Keyword(s):

High Sensitivity ◽

Soda Lime ◽

Dust Particles ◽

Soda Lime Glass ◽

High Noise ◽

M 10 ◽

Nasa Ames Research ◽

Characteristic Features ◽

The Masses ◽

The Impact

The composition of the impact-plasma, produced by dust particles hitting an Au-target was measured, using a model of the HELIOS-mlcrometeoroid-detector. The 2 MV dust accelerators of the MPI für Kernphysik, Heidelberg, and the NASA Ames Research Center were used to accelerate particles consisting of Al, Al2O3, SiO2, Soda-Lime-Glass, Polystyrene and Kaolin to velocities between 2 km/sec and 15 km/sec. Fe-projectiles could be accelerated up to 40 km/sec. The masses of the dust grains were between 10−15 g and 3 × 10−10 g. The experiments showed, that because of the characteristic features of the measured spectra it is possible to separate noise events from impacts even at a high noise background. The smallest particles (m 10−15 g) triggering the experiment produce spectra well above the noise level (more than a factor 10) because of the high sensitivity of the ion-detector (multiplier).

Download Full-text

DYNAMICAL CONSTRAINTS ON THE MASSES OF THE NUCLEAR STAR CLUSTER AND BLACK HOLE IN THE LATE-TYPE SPIRAL GALAXY NGC 3621

The Astrophysical Journal ◽

10.1088/0004-637x/690/1/1031 ◽

2008 ◽

Vol 690 (1) ◽

pp. 1031-1044 ◽

Cited By ~ 47

Author(s):

Aaron J. Barth ◽

Louis E. Strigari ◽

Misty C. Bentz ◽

Jenny E. Greene ◽

Luis C. Ho

Keyword(s):

Black Hole ◽

Spiral Galaxy ◽

Star Cluster ◽

Late Type ◽

Dynamical Constraints ◽

The Masses

Download Full-text

The velocity field of the Lyra complex

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936466 ◽

2020 ◽

Vol 633 ◽

pp. A108 ◽

Cited By ~ 1

Author(s):

M. Girardi ◽

W. Boschin ◽

S. De Grandi ◽

M. Longhetti ◽

S. Clavico ◽

...

Keyword(s):

Velocity Field ◽

High Velocity ◽

Major Axis ◽

Dynamical Analysis ◽

Cluster Assembly ◽

X Ray ◽

Radio Data ◽

The Galaxy ◽

A Minor ◽

Complex Scenario

Context. The formation of cosmic structures culminates with the assembly of galaxy clusters, a process that is quite different from cluster to cluster. Aims. We present the study of the structure and dynamics of the Lyra complex, consisting of the two clusters RXC J1825.3+3026 and CIZA J1824.1+3029, which was very recently studied by using both X-ray and radio data. Methods. This is the first analysis based on the kinematics of member galaxies. New spectroscopic data for 285 galaxies were acquired at the Italian Telescopio Nazionale Galileo and were used in combination with PanSTARRS photometry. The result of our member selection is a sample of 198 galaxies. Results. For RXCJ1825 and CIZAJ1824 we report the redshifts, z = 0.0645 and z = 0.0708, the first estimates of velocity dispersion, σv = 995+131−125 km s−1 and σv = 700 ± 50 km s−1, and of dynamical mass, M200 = 1.1 ± 0.4 × 1015 M⊙ and M200 = 4 ± 0.1 × 1014 M⊙. The past assembly of RXCJ1825 is traced by the two dominant galaxies, which are both aligned with the major axis of the galaxy distribution along the east–west direction, and by a minor northeast substructure. We also detect a quite peculiar high velocity field in the southwest region of the Lyra complex. This feature is likely related to a very luminous galaxy, which is characterized by a high velocity. This galaxy is suggested to be the central galaxy of a group that is in interaction with RXCJ1825 according to very recent studies based on X-ray and radio data. The redshift of the whole Lyra complex is z = 0.067. Assuming that the redshift difference between RXCJ1825 and CIZAJ1824 is due to the relative kinematics, the projected distance between the cluster centers is D ∼ 1.3 Mpc and the line–of–sight velocity difference is ∼1750 km s−1. A dynamical analysis of the system shows that the two clusters are likely to be gravitationally bound in a pre-merger phase, and that CIZAJ1824 is moving toward RXCJ1825. Conclusions. Our results corroborate a picture where the Lyra region is the place of a very complex scenario of cluster assembly.

Download Full-text

The velocity field of the barred spiral galaxy NGC 5383

The Astrophysical Journal ◽

10.1086/155752 ◽

1978 ◽

Vol 219 ◽

pp. 31 ◽

Cited By ~ 33

Author(s):

C. J. Peterson ◽

N. Thonnard ◽

V. C. Rubin ◽

W. K., Jr. Ford

Keyword(s):

Velocity Field ◽

Spiral Galaxy ◽

Barred Spiral Galaxy

Download Full-text

Design and Analysis of Thermal-Bubble-Based Micromachined Accelerometer

Volume 3 ◽

10.1115/esda2004-58152 ◽

2004 ◽

Author(s):

Ke-Min Liao ◽

Rongshun Chen ◽

Bruce C. S. Chou

Keyword(s):

Heat Transfer ◽

Fluid Flow ◽

Velocity Field ◽

Numerical Simulations ◽

Frequency Response ◽

Proof Mass ◽

Flow Behavior ◽

High Sensitivity ◽

The Other ◽

High Flux

In this study, a novel thermal-bubble-based micromachined accelerometer with advantages of no proof mass, preferable frequency response, and high sensitivity is presented. Unlike the other techniques, the only moving element in the proposed device is a small thermal-bubble created by using a high flux heater to vaporize the liquid contained in the micro chamber. In order to improve the performance of the accelerometer, the basic physical characteristics of this sensor have been analyzed. Numerical simulations are conducted to study the heat transfer and fluid flow behavior of the device and to demonstrate the feasibility of our design. The temperature profile and the velocity field distribution under different applied acceleration have been acquired. Moreover, a method for manufacturing the accelerometer by using the techniques of micromachining is provided and the performance of the presented design has been examined. The results concluded that the proposed design has better response and sensitivity comparing to its counterparts.

Download Full-text

Emission Line Profiles in RY Scuti: A Massive Binary in a Pre-WR Stage?

Symposium - International Astronomical Union ◽

10.1017/s0074180900045319 ◽

1991 ◽

Vol 143 ◽

pp. 261-262

Author(s):

D. de Martino ◽

A. A. Vittone ◽

C. Rossi ◽

F. Giovannelli

Keyword(s):

Velocity Field ◽

Main Sequence ◽

Log P ◽

Velocity Gradients ◽

Evolutionary Phase ◽

Mass Outflow ◽

Blue Component ◽

Type Contact ◽

Contact Binaries ◽

The Masses

RY Scuti (HD 169515) is a massive 9thmag eclipsing binary (Porb = 11.12d) surrounded by a peculiar nebula. High resolution spectroscopic observations in Hα, He I (λ5876), [N II] (λλ6548, 6584), [A III] (λ7136) and [S III] (λλ9069, 9532) are presented. All emission lines show a complex profile with two main structures: a sharp and strong red component and a very broad fainter complex blue one in which at least three sub-components can be detected. We have analysed these profiles in order to derive information on the velocity field in the nebula. Permitted and forbidden lines show the same velocity field indicating a common line forming region. The presence of a multi-structured blue component in all profiles gives evidence that velocity gradients are present within the nebula. Systemic corrected expansion velocities of + 30 and −45,−30,−9 Km/s are found for the red and the three blue components respectively. Weaker emission structures, reflecting the same asymmetries of the strong emissions, are observed close to the permitted lines at larger velocities (Vb = −189 Km/s and Vr = 158 K m/s). The observed velocity field indicates an asymmetric mass outflow from the system very likely through the second Lagrange point rather than via stellar wind. The system should loose mass during the mass exchange phase. Using the masses (M1 = 39M⊙, M2 = 49M⊙) and radii (R1 = 37R⊙, R2 = 41R⊙) of the two components (Milano et al., 1981), and locating RY Scuti in the [log R, log M] diagram for early type contact binaries from Leung and Schneider (1979), we find that this system has just evolved-off the Terminal Age Main Sequence. Moreover, placing RY Scuti in the [log P, log M1/M2] diagram for O+O and WR+OB binaries of Massey (1981) we find that it is in an evolutionary phase just preceeding a WR+OB stage.

Download Full-text