scholarly journals Interpretation of the Spatial Power Spectra of Neutral Hydrogen in the Galaxy and in the Small Magellanic Cloud

2000 ◽  
Vol 541 (2) ◽  
pp. 701-706 ◽  
Author(s):  
Itzhak Goldman
Keyword(s):  
Power Spectra ◽  
Neutral Hydrogen ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
The Galaxy

scholarly journals Star clusters in the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 161-164 ◽  
Author(s):  
S. van den Bergh
Keyword(s):  
Cluster Formation ◽  
Star Clusters ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Open Clusters ◽  
Small Magellanic Cloud ◽  
Cloud Clusters ◽  
The Galaxy

Star clusters in the Magellanic Clouds (MCs) differ from those in the Galaxy in a number of respects: (1) the Clouds contain a class of populous open clusters that has no Galactic counterpart; (2) Cloud clusters have systematically larger radii rh than those in the Galaxy; (3) clusters of all ages in the Clouds are, on average, more flattened than those in the Galaxy. In the Large Magellanic Cloud (LMC) there appear to have been two distinct epochs of cluster formation. LMC globulars have ages of 12-15 Gyr, whereas most populous open clusters have ages <5 Gyr. No such dichotomy is observed for clusters in the Small Magellanic Cloud (SMC) The fact that the SMC exhibits no enhanced cluster formation at times of bursts of cluster formation in the LMC, militates against encounters between the Clouds as a cause for enhanced rates of star and cluster formation.

scholarly journals A near-infrared VISTA of the Small Magellanic Cloud

2018 ◽  
Vol 14 (S344) ◽  
pp. 53-56
Author(s):  
Maria-Rosa L. Cioni ◽  
Florian Niederhofer ◽  
Stefano Rubele ◽  
Ning-Chen Sun
Keyword(s):  
Near Infrared ◽  
Stellar Populations ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Level Of Detail ◽  
Star Formation History ◽  
Main Body ◽  
Small Magellanic Cloud ◽  
Formation History ◽  
The Galaxy

AbstractVISTA observed the Small Magellanic Cloud (SMC), as part of the VISTA survey of the Magellanic Clouds system (VMC), for six years (2010–2016). The acquired multi-epoch YJKs images have allowed us to probe the stellar populations to an exceptional level of detail across an unprecedented wide area in the near-infrared. This contribution highlights the most recent VMC results obtained on the SMC focusing, in particular, on the clustering of young stellar populations, on the proper motion of stars in the main body of the galaxy and on the spatial distribution of the star formation history.

scholarly journals Spectroscopy of Overluminous Cepheids in the Magellanic Clouds

1984 ◽  
Vol 108 ◽  
pp. 223-224
Author(s):  
Horace A. Smith ◽  
Leo Connolly
Keyword(s):  
Globular Cluster ◽  
Large Magellanic Cloud ◽  
Variable Stars ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Small Magellanic Cloud ◽  
Single Star ◽  
Rr Lyrae ◽  
Short Period ◽  
The Galaxy

The Small Magellanic Cloud is known to contain types of short period Cepheid variable stars not yet discovered in either the Large Magellanic Cloud or, with the exception of a single star, in the Galaxy. These variables can be divided into two categories: anomalous Cepheids and Wesselink-Shuttleworth (WS) stars. The former, which have also been found in dwarf spheroidal systems and in the globular cluster NGC 5466, have periods of 0.4–3 days, but average 0.7–1.0 mag. brighter than RR Lyrae and BL Her stars of equal period. The stars we call WS stars have periods less than about 1.1 day and, at MV = −1 to −2, are brighter than anomalous Cepheids of equal period.

scholarly journals Spatial Variations of Turbulent Properties of Neutral Hydrogen Gas in the Small Magellanic Cloud Using Structure-function Analysis

2017 ◽  
Vol 845 (1) ◽  
pp. 53 ◽  
Author(s):  
David Nestingen-Palm ◽  
Snežana Stanimirović ◽  
Diego F. González-Casanova ◽  
Brian Babler ◽  
Katherine Jameson ◽  
...  
Keyword(s):  
Structure Function ◽  
Function Analysis ◽  
Neutral Hydrogen ◽  
Spatial Variations ◽  
Magellanic Cloud ◽  
Hydrogen Gas ◽  
Small Magellanic Cloud

scholarly journals The effect of metallicity on the Cepheid Period-Luminosity relation from a Baade-Wesselink analysis of Cepheids in the Galaxy and in the Small Magellanic Cloud

2004 ◽  
Vol 415 (2) ◽  
pp. 531-547 ◽  
Author(s):  
J. Storm ◽  
B. W. Carney ◽  
W. P. Gieren ◽  
P. Fouqué ◽  
D. W. Latham ◽  
...  
Keyword(s):  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
The Galaxy

scholarly journals Red supergiants in the Small Magellanic Cloud: The effects of metallicity on narrow-band classification indices

2004 ◽  
Vol 193 ◽  
pp. 317-321
Author(s):  
Robert F. Wing ◽  
Kyle M. Walker ◽  
D. Jack MacConnell ◽  
Edgardo Costa
Keyword(s):  
Near Infrared ◽  
Narrow Band ◽  
Variable Stars ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
Color System ◽  
The Galaxy ◽  
Red Supergiants

AbstractNarrow-band classification photometry, on a six-color system that measures near-infrared bands of TiO and CN, has been obtained for a set of red supergiants in the Small Magellanic Cloud. To investigate the effects of metallicity on the band-strength indices, comparisons are made to supergiants in the LMC and the Galaxy. Two new variable stars are reported.

scholarly journals Ring Nebulae Associated with Wolf-Rayet Stars

1982 ◽  
Vol 99 ◽  
pp. 469-472
Author(s):  
Y.-H. Chu
Keyword(s):  
Selection Criteria ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Small Magellanic Cloud ◽  
The Galaxy ◽  
Ring Nebulae ◽  
Strict Selection

Using strict selection criteria, we have searched for ring nebulae associated with Wolf-Rayet stars in the Galaxy and the Magellanic Clouds. In our search, 15 WR ring nebulae are identified in the Galaxy (Chu 1981a; Chu 1981b, Paper G1), 9 in the Large Magellanic Cloud, and none in the Small Magellanic Cloud (Chu and Lasker 1980, Paper LI; Chu 1981a). We have subsequently observed the morphology and kinematics of these 24 nebulae to study their nature. The data and analyses are reported in G (galactic) and L (LMC) series of papers. These nebulae and their references are listed in Table 1. This table is nearly, but not quite, complete. An extremely careful search might result in more cases, e.g., NGC6357 (Lortet et al. 1981). In a later search by Heckathorn et al. (1982), more ring nebulae are suggested; however, only three cases (associated with HD92740, HD187282, and HD211564) are more convincing. We have obtained some data for these nebulae and will discuss them in a conclusion paper of the galactic series (Chu et al. 1982, Paper G8).

HI in the Small Magellanic Cloud Re-examined

1981 ◽  
Vol 4 (2) ◽  
pp. 189-195 ◽  
Author(s):  
R. X. McGee ◽  
Lynette M. Newton
Keyword(s):  
Radial Velocity ◽  
Neutral Hydrogen ◽  
Total Content ◽  
Hii Regions ◽  
Magellanic Cloud ◽  
Hydrogen Gas ◽  
Radial Velocities ◽  
Line Of Sight ◽  
Small Magellanic Cloud

Our re-examination of the neutral hydrogen gas in the Small Magellan Cloud has led to four important results. Firstly, we find that Hindman’s (1967) total content HI map is a satisfactory representation of the gas in the line of sight. Secondly, we find that the HI gas in the SMC exists in four distinct large masses separated from one another in radial velocity by 20 to 30 km s−1. Thirdly, having made this division of the gas we show that there is good correlation between the radial velocities of HII regions, supergiant stars and HI. Finally, we believe that our observations reveal that the SMC is associated with an extremely large trailing halo of HI gas which forms the major component of the inter-cloud bridge region.

scholarly journals Quantifying EoR delay spectrum contamination from diffuse radio emission

2020 ◽  
Vol 494 (3) ◽  
pp. 3712-3727 ◽  
Author(s):  
Adam E Lanman ◽  
Jonathan C Pober ◽  
Nicholas S Kern ◽  
Eloy de Lera Acedo ◽  
David R DeBoer ◽  
...  
Keyword(s):  
Radio Emission ◽  
Large Scale ◽  
Power Spectra ◽  
Neutral Hydrogen ◽  
Spectral Structure ◽  
Wide Field ◽  
Electromagnetic Simulations ◽  
The Galaxy ◽  
Spectral Weighting ◽  
The Universe

ABSTRACT The 21 cm hyperfine transition of neutral hydrogen offers a promising probe of the large-scale structure of the universe before and during the Epoch of Reionization (EoR), when the first ionizing sources formed. Bright radio emission from foreground sources remains the biggest obstacle to detecting the faint 21 cm signal. However, the expected smoothness of foreground power leaves a clean window in Fourier space where the EoR signal can potentially be seen over thermal noise. Though the boundary of this window is well defined in principle, spectral structure in foreground sources, instrumental chromaticity, and choice of spectral weighting in analysis all affect how much foreground power spills over into the EoR window. In this paper, we run a suite of numerical simulations of wide-field visibility measurements, with a variety of diffuse foreground models and instrument configurations, and measure the extent of contaminated Fourier modes in the EoR window using a delay-transform approach to estimate power spectra. We also test these effects with a model of the Hydrogen Epoch of Reionization Array (HERA) antenna beam generated from electromagnetic simulations, to take into account further chromatic effects in the real instrument. We find that foreground power spillover is dominated by the so-called pitchfork effect, in which diffuse foreground power is brightened near the horizon due to the shortening of baselines. As a result, the extent of contaminated modes in the EoR window is largely constant over time, except when the Galaxy is near the pointing centre.

An H I Mosaic of the Small Magellanic Cloud

1995 ◽  
Vol 12 (1) ◽  
pp. 13-19 ◽  
Author(s):  
L. Staveley-Smith ◽  
R. J. Sault ◽  
D. McConnell ◽  
M. J. Kesteven ◽  
D. Hatzidimitriou ◽  
...  
Keyword(s):  
Star Formation ◽  
Neutral Hydrogen ◽  
Optical Emission ◽  
Magellanic Cloud ◽  
Molecular Gas ◽  
Small Magellanic Cloud ◽  
High Brightness ◽  
First Results ◽  
Low Metallicity ◽  
High Column

AbstractThis paper describes the first results from a 20 deg2 mosaic of the Small Magellanic Cloud (SMC) in the λ21-cm line of neutral hydrogen. The mosaic consists of 320 separate pointings with the 375-m array of the Australia Telescope Compact Array. The angular resolution is 1′· 5 (26 pc, for a distance of 60 kpc) and the velocity resolution is l·6kms−1. The images reveal a structure of remarkable complexity, with much of the spatial power contained in high-brightness temperature compact knots and filaments. Numerous wind-blown ‘bubbles’ and ‘supershells’ are evident in the data, both inside and outside the stellar confines of the SMC. Some high-density H I regions are seen to correlate with Hα regions, indicating sites of current star formation. However, many high-column-density H I regions are devoid of optical emission and may represent regions of future star formation. These regions may be under-abundant in diffuse molecular gas due to the high radiation field and low metallicity of the SMC.

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