Chandra Observations of NGC 253: New Insights into the Nature of Starburst-driven Superwinds

By D. Strickland, Tim Heckman, Kimberly A. Weaver, M. Dahlem. 2000

153 citations recorded by the source corpus.

Arcsecond-resolution X-ray imaging of the nucleus of the nearby starburst galaxy NGC 253 with Chandra reveals a well-collimated, strongly limb-brightened, kiloparsec-scale conical outflow from the central starburst region. The outflow is very similar in morphology to the known Hα outflow cone, on scales down to ≲20 pc. This provides, for the first time, robust evidence that both X-ray and Hα emission come from low volume filling factor regions of interaction between the fast energetic wind of SN ejecta and the denser ambient interstellar medium and not from the wind fluid itself. We provide estimates of the (observationally and theoretically important) filling factor of the X-ray–emitting gas, of between ∼4% and 40%, consistent with an upper limit of ∼40%, based directly on the observed limb-brightened morphology of the outflow. Only ≲20% of the observed X-ray emission can come from the volume-filling, metal-enriched, wind fluid itself. Spatially resolved spectroscopy of the soft diffuse thermal X-ray emission reveals that the predominant source of spectral variation along the outflow cones is due to strong variation in the absorption on scales of ∼60 pc, there being little change in the characteristic temperature of the emission. We show that these observations are easily explained by, and fully consistent with, the standard model of a superwind driven by a starburst of the observed power of NGC 253. If these results are typical of all starburst-driven winds, then we do not directly see all the energy and gas (in particular the hot metal-enriched gas) transported out of galaxies by superwinds, even in X-ray emission.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/f064324b0ca9f2c4c5f021ad713d1a6155e5a485

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Citations in the corpus

Three-Dimensional Simulations of a Starburst-driven Galactic Wind (2008, result): “One of the most striking results of these observations is the close spatial relationship with the H -emitting gas (e.g., Strickland et al. 2000, 2002, 2004a; Cecil et al. 2002; Martin et al. 2002; Grimes et al. 2005; Ott et al. 2005), suggesting a close physical connection.”
The SAMI Galaxy Survey: shocks and outflows in a normal star-forming galaxy (2014, background): “The conical structures are comprised predominately of warm and hot gas emitting in X-ray and optical line emission (e.g., Strickland et al. 2000; Cecil, Bland-Hawthorn & Veilleux 2002); these line-emitting structures are often limb-brightened.”
A High Spatial Resolution X-Ray and Hα Study of Hot Gas in the Halos of Star-forming Disk Galaxies. I. Spatial and Spectral Properties of the Diffuse X-Ray Emission (2003, methodology): “We originally targeted NGC 3079 as part of a program seeking to ascertain whether the close spatial correlation between X-ray and H emission found in the southern NGC 253 nuclear outflow cone (Strickland et al. 2000) is a general feature of all superwinds.”
Chandra Observations of “The Antennae” Galaxies (NGC 4038/4039). III. X-Ray Properties and Multiwavelength Associations of the X-Ray Source Population (2002, background): “…thermal component are reminiscent of those obtained for the superwinds in the nearby galaxies M82 and NGC 253 (Strickland, Ponman, & Stevens 1997; Strickland et al. 2000; Moran, Lehnert, & Helfand 1999), suggesting that a fraction of the total emission of these sources is produced by a…”
A High Spatial Resolution X-Ray and Hα Study of Hot Gas in the Halos of Star-forming Disk Galaxies. II. Quantifying Supernova Feedback (2003, background): “Another example is that the edges of best-resolved superwind outflows, in galaxies such as M82 and NGC 253, match up well to the edges of the nuclear starburst regions (Strickland & Stevens 2000; Strickland et al. 2000).”
THREE-DIMENSIONAL INTEGRAL FIELD OBSERVATIONS OF 10 GALACTIC WINDS. I. EXTENDED PHASE (≳10 Myr) OF MASS/ENERGY INJECTION BEFORE THE WIND BLOWS (2010, background): “X-ray observations do not reveal evidence for an AGN, being consistent with a starburst driven galactic wind (Persic et al. 1998; Strickland et al. 2000).”
An origin for multiphase gas in galactic winds and haloes (2015, background): “In accord with this view, the soft extraplanar X-ray emission from wind galaxies is often interpreted as shocked interfaces between the cool clouds and the surrounding hot medium (e.g., Strickland et al. 2000, 2002).”
An XMM-Newton hard X-ray survey of ultraluminous infrared galaxies (2003, background): “The warm thermal component is interpreted as originating from the boundary region between the hot, tenuous outgoing Galactic wind and the cool, dense interstellar medium (e.g. Strickland et al. 2000).”
Simulating galactic outflows with thermal supernova feedback (2012, background): “Indeed, observations do provide evidence for hot gas associated with fast galactic outflows (e.g. Heckman, Armus, & Miley 1987; Strickland et al. 2000; see also the review by Veilleux, Cecil, & Bland-Hawthorn 2005).”
X-ray emission from star-forming galaxies - II. Hot interstellar medium (2012, background): “The morphology of the diffuse X-ray emission suggests (e.g. Strickland et al. 2000) that the gas is in the state of outflow, driven by the collective effect of supernovae (SNe) and winds from massive stars E-mail: smineo@head.cfa.harvard.edu (e.g. Chevalier & Clegg 1985).”
Chandra Observations of NGC 253. II. On the Origin of Diffuse X-Ray Emission in the Halos of Starburst Galaxies (2001, methodology): “The ACIS spectrum of NGC 253’s southern nuclear outflow cone (Strickland et al. 2000) is spectrally harder (and therefore presumably hotter and/or more absorbed) than the diffuse emission in the halo.”
The Metal Content of Dwarf Starburst Winds: Results from Chandra Observations of NGC 1569 (2002, background): “In the NGC 253 superwind, the X-ray emission appears to come mainly from a boundary layer adjacent to the shell rather the entire interior of the bubble (Strickland et al. 2000).”