Probing the initial conditions of high-mass star formation - II. Fragmentation, stability, and chemistry towards high-mass star-forming regions G29.96−0.02 and G35.20−1.74

T. Pillai; J. Kauffmann; F. Wyrowski; J. Hatchell; A. G. Gibb; M. A. Thompson

doi:10.1051/0004-6361/201015899

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Volume 530 (June 2011)

A&A, 530 (2011) A118

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Table 6

Cores identified from the 1.3 mm and 3.5 mm continuum emission.

Core	Core offsets	S_peak	S_total	R_eff	T_kin	N_H₂	ρ	M_total	M_vir	α	M_aperture
	arcsec	Jy/beam	Jy	parsecs	(K)	(10²³ cm^-2)	(10⁵ cm^-3)	M_⊙	M_⊙		M_⊙

						G29.96e-1.3 mm
mm1	(2, 10)	0.052	0.293	0.16	23.	4.	2.	291.	90.	0.3	135.
mm2	(–2, 0)	0.026	0.200	0.17	16.^a	4.	2.	320.	55.	0.2	107.
mm3	(4, 16)	0.024	0.055	0.07	16.^a	4.	9.	88.	19.	0.2	90.
mm4	(4, 20)	0.020	0.051	0.08	16.^a	3.	6.	82.	13.	0.2	83.
mm5	(2, –14)^b	0.018	0.054	0.09	18.	2.	4.	74.	–	–	57.
mm6	(–1, 18)^c	0.014	0.036	0.07	16.^a	2.	6.	58.	–	–	45.
mm7	(–1, –24)	0.012	0.028	0.07	13.	2.	6.	60.	51.	0.8	32.
						G29.96e-3.5 mm
	(2, 10)	0.010	0.026	0.24	20.	5.	2.	836.	110.	0.1	225.
	(–1, 2)	0.007	0.017	0.21	20.	3.	2.	547.	64.	0.1	161.
	(2, –15)	0.003	0.005	0.14	17.	2.	2.	193.	42.	0.2	77.
						G35.20w-1.3 mm
mm1	(4, –1)	0.044	0.090	0.03	22.	5.	24.	18.	7.	0.4	17.
mm2	(16, 3)	0.030	0.059	0.03	21.	3.	17.	13.	9.	0.7	22.
mm3	(13, 2)^b	0.028	0.051	0.03	21.	3.	14.	11.	–	–	18.
mm4	(6, 12))^c^d	0.013	0.012	0.01	10.	5.	265.	8.	–	–	6.
						G35.20w-3.5 mm
	(4, –1)	0.017	0.078	0.15	20.	9.	5.	490.	107.	0.2	264.
	(15, 2)	0.011	0.046	0.13	19.	6.	5.	306.	145.	0.5	206.
	(–13, –11)	0.003	0.009	0.08	16.^a	2.	5.	78.	8.	0.1	48.
	(–15, 12)	0.003	0.005	0.06	16. ^a	2.	6.	40.	13.	0.3	32.

Notes. Columns are the clump name (for 1.3 mm cores only), offset position relative to the map center, peak flux, total flux, the effective radius after deconvolution with the beam of the mm core, total gas mass for a temperature T_kin estimated from NH₃ observations, peak H₂ column density, average gas density over R_eff, total mass, virial mass from NH₂D observations, the alpha parameter as defined in Eq. (2), and an aperture mass for an aperture size of 37 000 AU. 37 000 AU corresponds to the beam of the more distant source G29.96e. The aperture mass is underestimated up to a factor 2 when aperture size is very similar to the beam. Comments:

^(a)

Mass estimates based on an assumed temperature of 16 K, since measured value has a very high error (>30%).

^(b)

NH₂D spectra at these offsets show clearly more than one velocity component. We did not consider these positions because of the following, (i) poor two-component HFS fit in CLASS in one case, (ii) difficulty of associating a particular component to the dust.

^(c)

No NH₂D detection.

^(d)

mm4 is barely resolved with peak emission just above 5σ. Given the biases in a typical interferometer image, this might be spurious.

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