The Magellanic Stream, High-Velocity Clouds, and the Sculptor Group

By M. Putman, L. Staveley-Smith, Kenneth C. Freeman, B. Gibson, David G. Barnes. 2002

246 citations recorded by the source corpus.

The Magellanic Stream is a 100° × 10° filament of gas that lies within the Galactic halo and contains ~2 × 108 M☉ of neutral hydrogen. In this paper we present data from the H I Parkes All Sky Survey (HIPASS) in the first complete survey of the entire Magellanic Stream and its surroundings. We also present a summary of the reprocessing techniques used to recover large-scale structure in the Stream. The substantial improvement in spatial resolution and angular coverage compared to previous surveys reveals a variety of prominent features, including bifurcation along the main Stream filament; dense, isolated clouds that follow the entire length of the Stream; head-tail structures; and a complex filamentary web at the head of the Stream where gas is being freshly stripped away from the Small Magellanic Cloud and the Bridge. Debris that appears to be of Magellanic origin extends out to 20° from the main Stream filaments. The Magellanic Stream has a velocity gradient of 700 km s-1 from the Clouds to the tail of the Stream, ~390 km s-1 greater than that due to Galactic rotation alone, therefore implying a noncircular orbit. The dual filaments comprising the Stream are likely to be relics from gas stripped separately from the Magellanic Bridge and the SMC. This implies that (1) the Bridge is somewhat older than conventionally assumed; and (2) the Clouds have been bound together for at least one or two orbits. The transverse velocity gradient of the Stream also appears to support long-term binary motion of the Clouds. A significant number of the most elongated cataloged Stream clouds (containing ~1% of the Stream mass) have position angles aligned along the Stream. This suggests the presence of shearing motions within the Stream, arising from tidal forces or interaction with the tenuous Galactic halo. As previously noted, clouds within one region of the Stream, along the sight line to the less distant half (southern half on the sky) of the Sculptor Group, show anomalous properties. There are more clouds along this sight line than any other part of the Stream, and their velocity distribution significantly deviates from the gradient along the Stream. We argue that this deviation could be due to a combination of halo material, and not to distant Sculptor clouds, based on a spatial and kinematic comparison between the Sculptor Group galaxies and the anomalous clouds and the lack of cloud detection in the northern half of the group. This result has significant implications for the hypothesis that there might exist distant, massive high-velocity clouds within the Local Group. Cataloged clouds within the Magellanic Stream do not have a preferred scale size. Their mass spectrum f(M) ∝ M and column density spectrum f(N) ∝ N are steep compared with Lyα absorbers and galaxies, and similar to the anomalous clouds along the Sculptor Group sight line.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/4d9e17363f101e3d3447d7eceb53a1bb543777e7

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Citations in the corpus

The Parkes HI survey of the Magellanic System (2004, methodology): “We utilized early HIPASS maps from Putman et al. (2003a) to define the regions of interest with emission from the Magellanic Clouds and their gaseous arms.”
EIGHT ULTRA-FAINT GALAXY CANDIDATES DISCOVERED IN YEAR TWO OF THE DARK ENERGY SURVEY (2015, background): “This grouping of objects is projected onto a region of H I gas that is likely a secondary filament or high-velocity cloud associated with the head of the Magellanic Stream (Putman et al. 2003; McClure-Griffiths et al. 2009).”
SIMULATIONS OF THE MAGELLANIC STREAM IN A FIRST INFALL SCENARIO (2010, background): “The white line is a fit to the data (Putman et al. 2003; Nidever et al. 2008)[hereafter, N08] and shows good agreement with the simulation.”
Science with ASKAP (2008, background): “Some HVCs may be related to the Galactic Fountain; some are tidal debris connected to the Magellanic Stream [219] or other satellites; some may be infalling intergalactic gas, and some may be associated with Dark Matter halos and be the remnants of the formation of the Local Group.”
The total mass of the Large Magellanic Cloud from its perturbation on the Orphan stream (2018, background): “However, attempts to model the Magellanic stream seen in HI (Putman et al. 2003) have found that the SMC has likely had multiple pericentric passages with the LMC (e.g. Besla et al. 2012).”
The gravitational and hydrodynamical interaction between the Large Magellanic Cloud and the Galaxy (2004, methodology): “…the stripped material decelerated by ram-pressure forces could fall on smaller orbits and lead the Clouds (Sofue 1994; Moore & Davis 1994) – ram-pressure models are thought not to be able to reproduce the large amount of gas observed in the MS (∼2 × 108 M according to Putman et al. (2003a).”
The Origin of the Magellanic Stream and Its Leading Arm (2007, methodology): “In our database of H I Gaussians the MS appears as two filaments as has been previously re- ported by Putman et al. (2003).”
Probing Galactic Halos with Fast Radio Bursts (2019, unknown): “The Magellanic System (i.e., LMC/SMC and the H i stream; Putman et al. 2003; Nidever et al. 2008, 2010) can be seen with NHI & 1020 cm−2, together with some bright HVC structures such as Complex C (` ∼ 90, b ∼ 45), K (` ∼ 60, b ∼ 30), A (` ∼ 150, b ∼ 30), and WD (` ∼ 270, b ∼ 20) (Wakker 2001,…”
The Tumultuous Lives of Galactic Dwarfs and the Missing Satellites Problem (2004, background): “Another possibility is that most of the observed M31 CHVCs are gas clouds in tidal streams, such as the Magellanic Stream, and are not associated with distinct dark matter halos (Putman et al. 2003).”
Is the SMC Bound to the LMC? The Hubble Space Telescope Proper Motion of the SMC (2006, background): “Mass loss is probably significant, given the amount of matter in the Stream (estimated to be 2 ; 108 M , according to Putman et al. 2003).”
THIRD-EPOCH MAGELLANIC CLOUD PROPER MOTIONS. I. HUBBLE SPACE TELESCOPE/WFC3 DATA AND ORBIT IMPLICATIONS (2013, background): “…attention from the community in part because they require a new formation mechanism for the Magellanic Stream, a young coherent stream of H I gas that trails the Clouds ∼ 150◦ across the sky (Wannier & Wrixon 1972; Mathewson et al. 1974; Putman et al. 2003; Brüns et al. 2005; Nidever et al. 2010).”
Gaseous Galaxy Halos (2012, methodology): “None of the CHVCs or HVC complexes have a clear association with stellar features in the halo (Hopp et al., 2007; Siegel et al., 2005), excluding the association of MS and LA to the Magellanic Clouds.”
Hα Emission from High-Velocity Clouds and Their Distances (2003, background): “The Stream is a complicated network of filaments and clumps, but remains relatively continuous along its entire length (see Putman et al. 2003; hereafter P03).”
Are the Magellanic Clouds on Their First Passage about the Milky Way? (2007, background): “The orbits are traced backward in time until the LMC’s line-of-sight position vector subtends an angle of 100 with respect to its present-day position vector: this corresponds to the extent of theMS (Putman et al. 2003, hereafter P03).”
H i IN LOCAL GROUP DWARF GALAXIES AND STRIPPING BY THE GALACTIC HALO (2009, methodology): “…data cover the sky at δ < +25◦, and has been reprocessed using the MINMED5 algorithm which increases the sensitivity to resolved structures by using the entire 8◦ HIPASS scan to calculate the bandpass correction (rather than only using a 2◦section of the scan; see Putman et al. 2003 for details).”
Multiphase High-Velocity Clouds toward HE 0226–4110 and PG 0953+414 (2005, background): “This escape fraction is established from the intensity of H emission fromHVCswith known distance bounds (Bland-Hawthorn & Maloney 1999, 2002; Putman et al. 2003a), assuming that the H is photoionized.”
The role of dwarf galaxy interactions in shaping the Magellanic System and implications for Magellanic Irregulars (2012, background): “There is a well-defined velocity gradient along the length of the Stream (Putman et al. 2003; Nidever et al. 2008), ranging from 200 km s−1 near the Clouds to −400 km s−1.”
BEASTS OF THE SOUTHERN WILD: DISCOVERY OF NINE ULTRA FAINT SATELLITES IN THE VICINITY OF THE MAGELLANIC CLOUDS (2015, background): “Figure 22 compares the positions of the DES satellites to the distribution of HI in the Magellanic Stream as traced by Putman et al. (2003).”
A New Look at the Kinematics of Neutral Hydrogen in the Small Magellanic Cloud (2003, background): “In addition, as pointed out by Putman et al. (2003), a number of detailed features related to the Magellanic Stream (e.g., its double-helix appearance and the numerous small clouds surrounding its main filaments) need to be explained.”