A global view on star formation: the GLOSTAR Galactic plane survey

Ortiz-León, Gisela N.; Menten, K. M.; Brunthaler, A.; Csengeri, T.; Urquhart, J. S.; Wyrowski, F.; Gong, Y.; Rugel, M.; Dzib, Sergio A.; Yang, A. Y.; Nguyen, H.; Cotton, W. D.; Medina, S.; Dokara, R.; Koenig, C.; Beuther, H.; Pandian, J. D.; Reich, W.; Roy, Nirupam

doi:10.1051/0004-6361/202140817

Cited by 19 publications

(10 citation statements)

References 105 publications

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“…As mentioned above, a gradient in star formation activity over the region can be identified in which the western part already hosts an Hii region (near A) that is shown by the radio and strong mid-infrared emission. Region B also shows elevated temperatures, strong compact molecular emission, and a class II CH 3 OH maser found by Ortiz-León et al (2021). Class Article number, page 5 of 23 Fig.…”

Section: Resultsmentioning

confidence: 92%

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The Cygnus Allscale Survey of Chemistry and Dynamical Environments: CASCADE

Beuther

Wyrowski

Menten

et al. 2022

A&A

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Context. While star formation on large molecular cloud scales and on small core and disk scales has been investigated intensely over the past decades, the connection of the large-scale interstellar material with the densest small-scale cores has been a largely neglected field. Aims. We wish to understand how the gas is fed from clouds down to cores. This covers dynamical accretion flows as well as the physical and chemical gas properties over a broad range of spatial scales. Methods. Using the IRAM facilities NOEMA and the IRAM 30 m telescope, we mapped large areas (640 arcmin 2 ) of the archetypical star formation complex Cygnus X at 3.6 mm wavelengths in line and continuum emission. The data were combined and imaged together to cover all accessible spatial scales. Results. The scope and outline of The Cygnus Allscale Survey of Chemistry and Dynamical Environments (CASCADE) as part of the Max Planck IRAM Observatory Program (MIOP) is presented. We then focus on the first observed subregion in Cygnus X, namely the DR20 star formation site, which comprises sources in a range of evolutionary stages from cold pristine gas clumps to more evolved ultracompact Hii regions. The data covering cloud to cores scales at a linear spatial resolution of < 5000 au reveal several kinematic cloud components that are likely part of several large-scale flows onto the central cores. The temperature structure of the region is investigated by means of the HCN/HNC intensity ratio and compared to dust-derived temperatures. We find that the deuterated DCO + emission is almost exclusively located toward regions at low temperatures below 20 K. Investigating the slopes of spatial power spectra of dense gas tracer intensity distributions (HCO + , H 13 CO + , and N 2 H + ), we find comparatively flat slopes between −2.9 and −2.6, consistent with high Mach numbers and/or active star formation in DR20. Conclusions. This MIOP large program on star formation in Cyg X provides unique new data connecting cloud with core scales. The analysis of the DR20 data presented here highlights the potential of this program to investigate in detail the different physical and chemical aspects and their interrelations from the scale of the natal molecular cloud down to the scale of accretion onto the individual protostellar cores.

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Section: Resultsmentioning

confidence: 92%

“…A linear scale-bar is shown at the left. The six main regions A to F are marked, and a triangle shows the position of the class II CH 3 OH maser associated with B that has been determined by Ortiz-León et al (2021). be probed.…”

Section: Introductionmentioning

confidence: 99%

The Cygnus Allscale Survey of Chemistry and Dynamical Environments: CASCADE

Beuther

Wyrowski

Menten

et al. 2022

A&A

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“…Further investigation into shock tracers is warranted. Finally, high-resolution radio continuum observations in Cygnus X, for example with the Global View of Star Formation in the Milky Way survey (GLOSTAR) at 1 ′′ (e.g., Ortiz-León et al 2021), will reveal filamentary structure in unprecedented detail.…”

Section: Discussionmentioning

confidence: 99%

Filamentary structures of ionized gas in Cygnus X

Emig

White

Salas³

et al. 2022

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Context. Ionized gas probes the influence of massive stars on their environment. The Cygnus X region (d ~ 1.5 kpc) is one of the most massive star-forming complexes in our Galaxy, within which the Cyg OB2 association (age of 3–5 Myr and stellar mass 2 × 104 M⊙) has a dominant influence. Aims. We observe the Cygnus X region at 148 MHz using the Low Frequency Array (LOFAR) and take short-spacing information into account during image deconvolution into account. Together with data from the Canadian Galactic Plane Survey, we investigate the morphology, distribution, and physical conditions of low-density ionized gas in a 4° × 4° (~100 pc × 100 pc) region at a resolution of 2′ (0.9 pc). Methods. The Galactic radio emission in the region analyzed is almost entirely thermal (free-free) at 148 MHz, with emission measures (EM) of 103 < EM [pc cm−6] < 106. As filamentary structure is a prominent feature of the emission, we use DisPerSE and Fil ChaP to identify filamentary ridges and characterize their radial (EM) profiles. Results. The distribution of radial profiles has a characteristic width of 4.3 pc and a power-law distribution (β = −1.8 ± 0.1) in peak EM down to our completeness limit of 4200 pc cm−6. The electron densities of the filamentary structure range between 10 ≲ ne [cm−3] ≲ 400 with a median value of 35 cm−3, remarkably similar to [N II] surveys of ionized gas. Conclusions. Cyg OB2 may ionize at most two-thirds of the total ionized gas and the ionized gas in filaments. More than half of the filamentary structures are likely photoevaporating surfaces flowing into a surrounding diffuse (~5 cm−3) medium. However, this is likely not the case for all ionized gas ridges. A characteristic width in the distribution of ionized gas indicates that the stellar winds of Cyg OB2 create a fraction of the ionized filaments through swept-up ionized gas or dissipated turbulence.

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“…Absorption in the 6.7 GHz and 12.2 GHz CH 3 OH transitions is indeed detected towards several sources, several of which host I methanol masers (e.g. NGC2264 and DR21-W; Menten 1991a;Ortiz-León et al 2021), dark clouds (TMC1 and L183; Walmsley et al 1988), hot corinos (NGC1333; Pandian et al 2008), molecular clouds and HII region complexes (Peng & Whiteoak 1992), and the Galactic Centre regions (Sgr B2, Sgr A and G1.6−0.025; Whiteoak et al 1988;Houghton & Whiteoak 1995). 1 Methanol exists in two separate (non-interconverting) symmetry species: E-type and A-type CH 3 OH.…”

Section: Introductionmentioning

confidence: 95%

Redshifted methanol absorption tracing infall motions of high-mass star formation regions

Yang

Menten

Yang

et al. 2022

A&A

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Context. Gravitational collapse is one of the most important processes in high-mass star formation. Compared with the classic blue-skewed profiles, redshifted absorption against continuum emission is a more reliable method to detect inward motions within high-mass star formation regions. Aims. We aim to test if methanol transitions can be used to trace infall motions within high-mass star formation regions. Methods. Using the Effelsberg-100 m, IRAM-30 m, and APEX-12 m telescopes, we carried out observations of 37 and 16 methanol transitions towards two well-known collapsing dense clumps, W31C (G10.6−0.4) and W3(OH), to search for redshifted absorption features or inverse P-Cygni profiles. Results. Redshifted absorption is observed in 14 and 11 methanol transitions towards W31C and W3(OH), respectively. The infall velocities fitted from a simple two-layer model agree with previously reported values derived from other tracers, suggesting that redshifted methanol absorption is a reliable tracer of infall motions within high-mass star formation regions. Our observations indicate the presence of large-scale inward motions, and the mass infall rates are roughly estimated to be ≳10−3 M⊙ yr−1, which supports the global hierarchical collapse and clump-fed scenario. Conclusions. With the aid of bright continuum sources and the overcooling of methanol transitions leading to enhanced absorption, redshifted methanol absorption can trace infall motions within high-mass star formation regions hosting bright H II regions.

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A global view on star formation: the GLOSTAR Galactic plane survey

Cited by 19 publications

References 105 publications

The Cygnus Allscale Survey of Chemistry and Dynamical Environments: CASCADE

The Cygnus Allscale Survey of Chemistry and Dynamical Environments: CASCADE

Filamentary structures of ionized gas in Cygnus X

Redshifted methanol absorption tracing infall motions of high-mass star formation regions

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