SOFIA FEEDBACK Survey: Exploring the Dynamics of the Stellar Wind–Driven Shell of RCW 49

Tiwari, M.; Karim, R.; Pound, Marc W.; Wolfire, M. G.; Jacob, A. M.; Buchbender, C.; Güsten, R.; Guevara, C.; Higgins, R.; Kabanovic, S.; Pabst, C. H. M.; Ricken, Oliver; Schneider, N.; Simon, R.; Stutzki, J.; Tielens, A. G. G. M.

doi:10.3847/1538-4357/abf6ce

Cited by 38 publications

(84 citation statements)

References 66 publications

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“…As mentioned in the introduction, the existence of expanding shell-like structures around HII regions and PDRs is a recurring result of the SOFIA FEEDBACK program, where NGC 7538 is part of, as well as other [CII] studies. The best studied examples are Orion (Pabst et al 2019), RCW120 (Luisi et al 2021), and RCW49 (Tiwari et al 2021). From a geometry point of view, the Orion Veil and RCW120 exhibit more complete shell-like structures in the [CII] emission.…”

Section: Shell Structures Associated With Hii Regions and Pdrs In [Ci...mentioning

confidence: 99%

“…More details about this SOFIA legacy program are provided in Schneider et al (2020). One outcome of the FEEDBACK project so far is the detection of expanding shells in [CII] emission in various bubble-shaped or bipolar HII regions, namely, in RCW120 (Luisi et al 2021;Kabanovic et al 2022), RCW49 (Tiwari et al 2021), RCW36 (Bonne et al 2022), and RCW79 (Zavagno et al, in prep.). These shells were first detected in Orion A (Pabst et al 2019) and appear to be a ubiquitous phenomena.…”

Section: Introductionmentioning

confidence: 99%

“…These shells were first detected in Orion A (Pabst et al 2019) and appear to be a ubiquitous phenomena. While the regions RCW49 and RCW120 reveal second -generation star formation within these shells (Tiwari et al 2021;Luisi et al 2021), the expanding veil nebula in Orion shows little evidence of dense clumps that could lead to star formation (Pabst et al 2019;Goicoechea et al 2020).…”

Section: Introductionmentioning

confidence: 99%

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FEEDBACK from the NGC 7538 H II region

Beuther

Schneider

Simon

et al. 2022

A&A

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Context. The interaction of expanding H II regions with their environmental clouds is one of the central questions driving the Stratospheric Observatory for Infrared Astronomy (SOFIA) legacy program FEEDBACK. Aims. We want to understand the interaction of the prototypical NGC 7538 H II region with the neighboring molecular cloud hosting several active star-forming regions. Methods. Using the SOFIA, we mapped an area of ~210′2 (~125 pc2) around NGC 7538 in the velocity-resolved ionized carbon fine-structure line [CII] at 1.9 THz (158 μm). Complementary observed atomic carbon [CI] at 492 GHz and high-J CO(8–7) data, as well as archival near- and far-infrared, cm continuum, CO(3–2), and HI data are folded into the analysis. Results. The ionized carbon [CII] data reveal rich morphological and kinematic structures. While the overall morphology follows the general ionized gas that is also visible in the radio continuum emission, the channel maps show multiple bubble-like structures with sizes on the order of ~80–100″ (~1.0–1.28 pc). While at least one of them may be an individual feedback bubble driven by the main exciting sources of the NGC 7538 H II region (the O3 and O9 stars IRS6 and IRS5), the other bubble-like morphologies may also be due to the intrinsically porous structure of the H II region. An analysis of the expansion velocities around 10 km s−1 indicates that thermal expansion is not sufficient but that wind-driving from the central O-stars is required. The region exhibits a general velocity gradient across, but we also identify several individual velocity components. The most blue-shifted [CII] component has barely any molecular or atomic counterparts. At the interface to the molecular cloud, we find a typical photon-dominated region (PDR) with a bar-shape. Ionized C+, atomic C0 and molecular carbon CO show a layered structure in this PDR. The carbon in the PDR is dominated by its ionized C+ form with atomic C0 and molecular CO masses of ~0.45 ± 0.1 M⊙ and ~1.2 ± 0.1 M⊙, respectively, compared to the ionized carbon C+ in the range of 3.6−9.7 M⊙. This bar-shaped PDR exhibits a velocity-gradient across, indicating motions along the line of sight toward the observer. Conclusions. Even if it is shown to be dominated by two nearby exciting sources (IRS6 and IRS5), the NGC 7538 H II region exhibits a diverse set of substructures that interact with each other as well as with the adjacent cloud. Compared to other recent [CII] observations of H II regions (e.g., Orion Veil, RCW120, RCW49), the bubble-shape morphologies revealed in [CII] emission that are indicative of expanding shells are recurring structures of PDRs.

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Section: Shell Structures Associated With Hii Regions and Pdrs In [Ci...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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FEEDBACK from the NGC 7538 H II region

Beuther

Schneider

Simon

et al. 2022

A&A

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“…Velocity resolved line profiles of [C II] and [O I] used in combination with other tracers such as [C I] and CO reveal outflows (e.g., Schneider et al 2018), thermal and non-thermal pressures (e.g., Goicoechea et al 2015, Pérez-Beaupuits et al 2015, multiple PDR components (e.g., Dedes et al 2010, Seo et al 2019, and can separate the neutral and ionized gas. For example, line widths suggest an equipartition of thermal, turbulent, and magnetic pressures in the PDRs associated with the Orion region and RCW 49 (Tiwari et al 2021. Anderson et al (2019) find that the (velocity resolved) [N II] 205 µm emission in S235 is clearly velocity shifted from the [C II] emission and only ∼10% of the [C II] comes from the neutral gas 15 .…”

Section: Preparation)mentioning

confidence: 99%

Photodissociation and X-Ray Dominated Regions

Wolfire¹,

Vallini²,

Chevance³

2022

Preprint

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The radiation from stars and active galactic nuclei (AGN) creates photodissociation regions (PDRs) and X-ray dominated regions (XDRs), where the chemistry or heating are dominated by far-ultraviolet (FUV) radiation or X-ray radiation, respectively. PDRs include a wide range of environments from the diffuse interstellar medium to dense star-forming regions. XDRs are found in the center of galaxies hosting AGN, in protostellar disks, and in the vicinity of X-ray binaries. In this review, we describe the dominant thermal, chemical, and radiation transfer processes in PDRs and XDRs, as well as a brief description of models and their use to analyze observations. We then present recent results from Milky Way, nearby extragalactic, and high-redshift observations. Several important results are:

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“…We used an estimate for the shockwave expansion velocity of 15 km s −1 (e.g. Tiwari et al 2021;Luisi et al 2021;Patel et al 1998) to estimate the age of the pillars and the shockwave. Including all of the pillars shown in Figure 15 resulted in an average expansion time of 1.2 Myr.…”

Section: Ysos In Pillarsmentioning

confidence: 99%

Testing Models of Triggered Star Formation with Young Stellar Objects in Cepheus OB4

Mintz,

Hora,

Winston

2021

Preprint

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OB associations are home to newly formed massive stars, whose turbulent winds and ionizing flux create H II regions rich with star formation. Studying the distribution and abundance of young stellar objects (YSOs) in these ionized bubbles can provide essential insight into the physical processes that shape their formation, allowing us to test competing models of star formation. In this work, we examined one such OB association, Cepheus OB4 (Cep OB4) -a well-suited region for studying YSOs due to its Galactic location, proximity, and geometry. We created a photometric catalog from Spitzer /IRAC mosaics in bands 1 (3.6 µm) and 2 (4.5 µm). We supplemented the catalog with photometry from WISE, 2MASS, IRAC bands 3 (5.8 µm) and 4 (8.0 µm), MIPS 24 µm, and MMIRS near IR data. We used color-color selections to identify 821 YSOs, which we classified using the IR slope of the YSOs' spectral energy distributions (SEDs), finding 67 Class I, 103 flat spectrum, 569 Class II, and 82 Class III YSOs. We conducted a clustering analysis of the Cep OB4 YSOs and fit their SEDs. We found many young Class I objects distributed in the surrounding shell and pillars as well as a relative age gradient of unclustered sources, with YSOs generally decreasing in age with distance from the central cluster. Both of these results indicate that the expansion of the H II region may have triggered star formation in Cep OB4.

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SOFIA FEEDBACK Survey: Exploring the Dynamics of the Stellar Wind–Driven Shell of RCW 49

Cited by 38 publications

References 66 publications

FEEDBACK from the NGC 7538 H II region

FEEDBACK from the NGC 7538 H II region

Photodissociation and X-Ray Dominated Regions

Testing Models of Triggered Star Formation with Young Stellar Objects in Cepheus OB4

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SOFIA FEEDBACK Survey: Exploring the Dynamics of the Stellar Wind–Driven Shell of RCW 49

Cited by 38 publications

References 66 publications

FEEDBACK from the NGC 7538 H II region

FEEDBACK from the NGC 7538 H II region

Photodissociation and X-Ray Dominated Regions

Testing Models of Triggered Star Formation with Young Stellar Objects in Cepheus OB4

Contact Info

Product

Resources

About

FEEDBACK from the NGC 7538 H II region

FEEDBACK from the NGC 7538 H II region