Multiband far-infrared observations of the NGC 6334 complex

Loughran, L.; McBreen, B.; Fazio, G. G.; Rengarajan, T. N.; Maxson, C. W.

doi:10.1086/164112

Cited by 50 publications

(55 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An anisotropic dust distribution in the UC H ii region or the presence of undetected (obscured) stars may account for this discrepancy between the IRAS luminosity and the luminosity of the observed near-IR stellar population (see the general discussion in x 4.2.4). NGC 6334-V is a far-IR source ( McBreen et al 1979;Loughran et al 1986) in the complex star-forming region NGC 6334. In the original low-resolution map at 69 m by McBreen et al (1979), NGC 6334-V appears as a point source at a resolution of $3 0 .…”

Section: Discussion On Indivv Idual Regg Ionsmentioning

confidence: 99%

Near‐Infrared Subarcsecond Observations of Ultracompact H ii Regions

Álvarez

Feldt

Henning

et al. 2004

ASTROPHYS J SUPPL S

View full text Add to dashboard Cite

We present adaptive optics (AO) assisted J, H, and K=K 0 images of eight ultracompact H ii (UC H ii) regions taken with the ALFA and ADONIS AO systems at Calar Alto and La Silla observatories. The images show details of the stellar population and the near-IR morphology of UC H ii regions with unprecedented resolution. We have searched for the ionizing sources of the regions using near-IR photometry. The spectral type of the ionizing and most luminous stars inferred from our photometry has been compared with spectral type estimates from IRAS and published radio-continuum measurements. We find that the photometric near-IR spectral types are earlier than estimates from radio and IRAS data. This difference is alleviated when stellar spherical models including line blanketing and stellar winds instead of non-LTE plane-parallel models are used to derive the radio-and IRASbased spectral types. We also made an attempt to correlate the properties of the near-IR ionizing population with MSX data and published CS measurements. No correlation was found. We note that in two of the regions (G309.92+0.48 and G61.48+0.09B1), the best candidate to ionize the region is possibly a supergiant.

show abstract

Section: Discussion On Indivv Idual Regg Ionsmentioning

confidence: 99%

Near‐Infrared Subarcsecond Observations of Ultracompact H ii Regions

Álvarez

Feldt

Henning

et al. 2004

ASTROPHYS J SUPPL S

View full text Add to dashboard Cite

show abstract

“…(2) Loughran et al (1986). ( than a centrally-concentrated starless MDC hosting a high-mass prestellar core.…”

Section: Quest For High-mass Prestellar Cores In Mdcsmentioning

confidence: 99%

The earliest phases of high-mass star formation, as seen in NGC 6334 by Herschel-HOBYS

Tigé

Motte

Russeil

et al. 2017

A&A

View full text Add to dashboard Cite

Aims. To constrain models of high-mass star formation, the Herschel-HOBYS key program aims at discovering massive dense cores (MDCs) able to host the high-mass analogs of low-mass prestellar cores, which have been searched for over the past decade. We here focus on NGC 6334, one of the best-studied HOBYS molecular cloud complexes. Methods. We used Herschel/PACS and SPIRE 70−500 µm images of the NGC 6334 complex complemented with (sub)millimeter and mid-infrared data. We built a complete procedure to extract ∼0.1 pc dense cores with the getsources software, which simultaneously measures their far-infrared to millimeter fluxes. We carefully estimated the temperatures and masses of these dense cores from their spectral energy distributions (SEDs). We also identified the densest pc-scale cloud structures of NGC 6334, one 2 pc × 1 pc ridge and two 0.8 pc × 0.8 pc hubs, with volume-averaged densities of ∼10 5 cm −3 . Results. A cross-correlation with high-mass star formation signposts suggests a mass threshold of 75 M for MDCs in NGC 6334. MDCs have temperatures of 9.5−40 K, masses of 75−1000 M , and densities of 1 × 10 5 −7 × 10 7 cm −3 . Their mid-infrared emission is used to separate 6 IR-bright and 10 IR-quiet protostellar MDCs while their 70 µm emission strength, with respect to fitted SEDs, helps identify 16 starless MDC candidates. The ability of the latter to host high-mass prestellar cores is investigated here and remains questionable. An increase in mass and density from the starless to the IR-quiet and IR-bright phases suggests that the protostars and MDCs simultaneously grow in mass. The statistical lifetimes of the high-mass prestellar and protostellar core phases, estimated to be 1−7 × 10 4 yr and at most 3 × 10 5 yr respectively, suggest a dynamical scenario of high-mass star formation. Conclusions. The present study provides good mass estimates for a statistically significant sample, covering the earliest phases of high-mass star formation. High-mass prestellar cores may not exist in NGC 6334, favoring a scenario presented here, which simultaneously forms clouds, ridges, MDCs, and high-mass protostars.

show abstract

“…At sub-millimetre wavelengths, the central part of NGC 6334 consists of a 10-pc long filament that is also associated with strong extinction (Russeil et al 2010). Several sites of high-mass star formation have been identified (e.g., Loughran et al 1986), by the presence of water masers, UC H ii regions (e.g., Rodriguez et al 1982;Carral et al 2002), molecular outflows, and H ii regions (GUM 61, 62, 63, and 64 (Gum 1955), and GM1-24, indicated in Fig. 1).…”

Section: The Ngc 6334 Star-formation Complexmentioning

confidence: 99%

TheHerschelview of the massive star-forming region NGC 6334

Russeil

Schneider

Anderson

et al. 2013

A&A

View full text Add to dashboard Cite

Aims. Fundamental to any theory of high-mass star formation are gravity and turbulence. Their relative importance, which probably changes during cloud evolution, is not known. By investigating the spatial and density structure of the high-mass star-forming complex NGC 6334 we aim to disentangle the contributions of turbulence and gravity. Methods. We used Herschel PACS and SPIRE imaging observations from the HOBYS key programme at wavelengths of 160, 250, 350, and 500 μm to construct dust temperature and column density maps. Using probability distribution functions (PDFs) of the column density determined for the whole complex and for four distinct sub-regions (distinguished on the basis of differences in the column density, temperature, and radiation field), we characterize the density structure of the complex. We investigate the spatial structure using the Δ-variance, which probes the relative amount of structure on different size scales and traces possible energy injection mechanisms into the molecular cloud. Results. The Δ-variance analysis suggests that the significant scales of a few parsec that were found are caused by energy injection due to expanding H ii regions, which are numerous, and by the lengths of filaments seen everywhere in the complex. The column density PDFs have a lognormal shape at low densities and a clearly defined power law at high densities for all sub-regions whose slope is linked to the exponent α of an equivalent spherical density distribution. In particular with α = 2.37, the central sub-region is largly dominated by gravity, caused by individual collapsing dense cores and global collapse of a larger region. The collapse is faster than free-fall (which would lead only to α = 2) and thus requires a more dynamic scenario (external compression, flows). The column density PDFs suggest that the different sub-regions are at different evolutionary stages, especially the central sub-region, which seems to be in a more evolved stage.

show abstract

Multiband far-infrared observations of the NGC 6334 complex

Cited by 50 publications

References 0 publications

Near‐Infrared Subarcsecond Observations of Ultracompact H ii Regions

Near‐Infrared Subarcsecond Observations of Ultracompact H ii Regions

The earliest phases of high-mass star formation, as seen in NGC 6334 by Herschel-HOBYS

TheHerschelview of the massive star-forming region NGC 6334

Contact Info

Product

Resources

About