The Cygnus Allscale Survey of Chemistry and Dynamical Environments: CASCADE

Abstract

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.

The Green Bank 820 MHz Pulsar Survey. I. Survey Overview and Initial Results

“…The Cygnus region observed in this work is known to harbor many sites of star formation, including extensive OB associations (Comerón & Pasquali 2012;Berlanas et al 2019;Quintana & Wright 2021;Orellana et al 2021;Quintana & Wright 2022), Wolf-Rayet (W-R) stars (Koch-Miramond et al 2002;Rauw et al 2015), and H II regions (Beerer et al 2010;Emig et al 2022). As such, it has been invaluable for studying the entire life cycle of stars-many of which have formed within the past few million years (van der Walt et al 2021;Beuther et al 2022). Many of these studies have focused on the relatively nearby (;1.4 kpc; Rygl et al 2012;Orellana et al 2021) star-forming region along this line of sight, known as Cygnus X (Piddington & Minnett 1952).…”

Surveying the Whirlpool at Arcseconds with NOEMA (SWAN)

“…Galactic studies do not find correlations between N 2 H + and midinfrared (MIR) photons (e.g. Beuther et al 2022) suggesting that N 2 H + is not affected by infrared-pumping via the AGN. While an increased temperature in the AGN vicinity can also increase HCN emission (Matsushita et al 2015;Tafalla et al 2023), this would lead to CO sublimating, reacting with and destroying N 2 H + in contrast to our findings.…”

“…Galactic studies have questioned the use of HCN as a dense gas tracer at cloud scales (<10 pc) and favour the use of another molecule, N 2 H + , which has successfully been detected towards several molecular clouds in the Milky Way (e.g. Pety et al 2017;Kauffmann et al 2017; Barnes et al 2020;Tafalla et al 2021Tafalla et al , 2023Beuther et al 2022;Santa-Maria et al 2023). Since N 2 H + is destroyed in the presence of CO, it is linked to the dense clumps of clouds, where CO freezes to dust grains (e.g.…”

Data Combination: Interferometry and Single-dish Imaging in Radio Astronomy

“…For example, in the case of the Atacama Large Millimeter/submillimeter Array (ALMA), this is done by combining data from the main ALMA 12 m array and/or the ALMA 7 m Compact Array (ACA) with data from the dedicated ALMA SD (or total power, TP) telescopes. A broad literature highlights the critical role of data combination in both Galactic and extragalactic studies, including a large variety of interferometer-plus-SD combinations not only within ALMA (for a very thorough example, see Leroy et al 2021, among others) but also using the CARMA and NRO 45 m/IRAM 30 m/FCRAO (Koda et al 2011;Plunkett et al 2013Plunkett et al , 2015Kong et al 2018), SMA and APEX (Kauffmann et al 2017), (E)JVLA and GBT (Pineda et al 2011;Williams et al 2018;Wang et al 2020), PdBI/NOEMA and IRAM 30 m (Pety et al 2013;Beuther et al 2022), ALMA 12 m and MOPRA/IRAM 30 m (Peretto et al 2013;Hacar et al 2018), or ASKAP and Parkes (Pingel et al 2022) telescopes, to cite some examples.…”