Display data from paper

Select data type:

SOB18 - Sun-sized Water Vapor Masers in Cepheus A

Interferometry data

Short title: Sobolev et al. (2018)
Authors: Sobolev, A. M. Moran, J. M. Gray, M. D. Alakoz, A. Imai, H. Baan, W. A. Tolmachev, A. M. Samodurov, V. A. Ladeyshchikov, D. A.
Journal: The Astrophysical Journal, Volume 856, Issue 1, article id. 60, 9 pp. (2018).
Bibcode:

Target type: High_mass_SFR

Abstract
We present the first VLBI observations of a Galactic water maser (in Cepheus A) made with a very long baseline interferometric array involving the RadioAstron Earth-orbiting satellite station as one of its elements. We detected two distinct components at -16.9 and 0.6 km s^-1 with a fringe spacing of 66 muas. In total power, the 0.6 km s^-1 component appears to be a single Gaussian component of strength 580 Jy and width of 0.7 km s^-1. Single-telescope monitoring showed that its lifetime was only eight months. The absence of a Zeeman pattern implies the longitudinal magnetic field component is weaker than 120 mG. The space-Earth cross power spectrum shows two unresolved components smaller than 15 muas, corresponding to a linear scale of 1.6 � 10¹¹ cm, about the diameter of the Sun, for a distance of 700 pc, separated by 0.54 km s^-1 in velocity and by 160 � 35 muas in angle. This is the smallest angular structure ever observed in a Galactic maser. The brightness temperatures are greater than 2 � 10¹⁴ K, and the line widths are 0.5 km s^-1. Most of the flux (about 87%) is contained in a halo of angular size of 400 � 150 muas. This structure is associated with the compact H II region HW3diii. We have probably picked up the most prominent peaks in the angular size range of our interferometer. We discuss three dynamical models: (1) Keplerian motion around a central object, (2) two chance overlapping clouds, and (3) vortices caused by flow around an obstacle (i.e., von K�rm�n vortex street) with a Strouhal number of about 0.3. eprintid: arXiv:1802.06756

Abstract

We present the first VLBI observations of a Galactic water maser (in Cepheus A) made with a very long baseline interferometric array involving the RadioAstron Earth-orbiting satellite station as one of its elements. We detected two distinct components at -16.9 and 0.6 km s^-1 with a fringe spacing of 66 muas. In total power, the 0.6 km s^-1 component appears to be a single Gaussian component of strength 580 Jy and width of 0.7 km s^-1. Single-telescope monitoring showed that its lifetime was only eight months. The absence of a Zeeman pattern implies the longitudinal magnetic field component is weaker than 120 mG. The space-Earth cross power spectrum shows two unresolved components smaller than 15 muas, corresponding to a linear scale of 1.6 � 10¹¹ cm, about the diameter of the Sun, for a distance of 700 pc, separated by 0.54 km s^-1 in velocity and by 160 � 35 muas in angle. This is the smallest angular structure ever observed in a Galactic maser. The brightness temperatures are greater than 2 � 10¹⁴ K, and the line widths are 0.5 km s^-1. Most of the flux (about 87%) is contained in a halo of angular size of 400 � 150 muas. This structure is associated with the compact H II region HW3diii. We have probably picked up the most prominent peaks in the angular size range of our interferometer. We discuss three dynamical models: (1) Keplerian motion around a central object, (2) two chance overlapping clouds, and (3) vortices caused by flow around an obstacle (i.e., von K�rm�n vortex street) with a Strouhal number of about 0.3. eprintid:

Download as: Table (CSV)
View as list of objects

Detection table from Sobolev et al. (2018)

Export table to csv

Hide / Show individual components

ID	Obs. RA	Obs. Dec	RA offset	Dec offset	l	b	Group id	#	Maser spot	Source name	Image	Descr.	Line	V_peak	F_peak	Telescope	V_step	RMS	Detection	Class	Dist. (parallax)
	(J2000)	(J2000)	(mas)	(mas)	(deg.)	(deg.)							H₂O	(km/s)	(Jy)		(km/s)	(Jy)	Yes/No		(kpc)
1	+22 56 17.977	+62 01 49			109.870934	2.114158	G109.871+2.114			CepA	Image	Descr	22 GHz;	-16.9 .. 0.6	55 .. 800	RA	0.105	444.000	+H₂O +CH₃OH I +CH₃OH II +OH	SFR
	+22 56 18.017	+62 01 51.2908	600 mas	2290 mas	109.871277	2.114700		1	HW3diii	CepA				0.6	580
	+22 56 17.3303	+62 01 50.6408	-9700 mas	1640 mas	109.869987	2.115112		2	HW3dii	CepA				-9.7	800
	+22 56 16.9903	+62 01 49.0508	-14800 mas	50 mas	109.869197	2.114998		3	HW2	CepA				-14.8	55
	+22 56 16.897	+62 01 49.0108	-16200 mas	10 mas	109.869027	2.115066		4	HW2	CepA				-16.2	130
	+22 56 16.8503	+62 01 49.0008	-16900 mas	0 mas	109.868944	2.115103		5	HW2	CepA				-16.9	152

DSS colored	2MASS colored	WISE colored
PACS color (70-160 um)	SPIRE color (250-500 um)	GLIMPSE 360
SDSS color	IRAC color I1,I2,I4	NVSS (1.4GHz)
ATLASGAL 870 um	ATLASGAL 870 um + Planck	Bolocam 1.1 mm
UKIDSS K Download UKIDSS K FITS	2MASS K Download 2MASS K FITS

select MAX(h2o_data_all.ra_hms) as ra_hms,MAX(h2o_data_all.dec_dms) as dec_dms,MAX(h2o_data_all.source_name) as source_name,MAX(h2o_data_all.ra) as ra,MAX(h2o_data_all.dec) as dec,MAX(h2o_data_all.l) as l,MAX(h2o_data_all.b) as b,MAX(h2o_data_all.grp) as grp,MAX(h2o_data_all.other_name) as other_name,MAX(h2o_data_all.other_desc) as other_desc,BOOL_OR(thermal) as thermal,MAX(h2o_data_all.line) as line,MAX(h2o_data_all.vrange) as vrange,MAX(h2o_data_all.vpeak) as vpeak,MAX(h2o_data_all.peak) as peak,MAX(h2o_data_all.fwhm) as fwhm,MAX(h2o_data_all.int) as int,MAX(h2o_data_all.rms) as rms,MAX(h2o_data_all.units) as units,MAX(h2o_data_all.units_rms) as units_rms,MAX(h2o_data_all.date_txt) as date_txt,MAX(h2o_data_all.telescope_ref) as telescope_ref,MAX(h2o_data_all.telescope_conf) as telescope_conf,MAX(h2o_data_all.v_step) as v_step,MAX(h2o_data_all.beam) as beam,MAX(h2o_data_all.beam_maj) as beam_maj,MAX(h2o_data_all.beam_min) as beam_min,MAX(h2o_data_all.beam_pa) as beam_pa,MAX(h2o_data_all.ref) as ref,MAX(h2o_data_all.list_ref) as list_ref,MAX(h2o_data_all.ascii) as ascii,MAX(h2o_data_all.url) as url,MAX(h2o_data_all.image) as image,MAX(h2o_data_all.image2) as image2,MAX(h2o_data_all.image3) as image3,MAX(h2o_data_all.descr) as descr,MAX(h2o_data_all.id) as id,BOOL_OR(mjy_flag) as mjy_flag,BOOL_OR(rms_mjy_flag) as rms_mjy_flag,MAX(h2o_data_all.dist) as dist,1 as dist_parallax,MAX(h2o_data_all.date_txt) as date_txt,MAX(line_det) as line_det,MAX(type) as type,MAX(simbad_types_cat) as simbad_types_cat FROM h2o_data_all  LEFT JOIN all_objects_withmet ON h2o_data_all.grp=all_objects_withmet.group_name LEFT JOIN object_categories ON all_objects_withmet.group_name = object_categories.group_name_cat AND object_categories.tbl_cat = 'all_objects_withmet' LEFT JOIN transitions ON h2o_data_all.line=transitions."Line"  WHERE ref ilike 'SOB18' AND detected=true AND hide=false GROUP BY ref

select h2o_data_all.ra_hms,h2o_data_all.dec_dms,h2o_data_all.source_name,h2o_data_all.ra,h2o_data_all.dec,h2o_data_all.l,h2o_data_all.b,h2o_data_all.grp,h2o_data_all.other_name,h2o_data_all.other_desc,h2o_data_all.thermal,h2o_data_all.line,h2o_data_all.vrange,h2o_data_all.vpeak,h2o_data_all.peak,h2o_data_all.fwhm,h2o_data_all.int,h2o_data_all.rms,h2o_data_all.units,h2o_data_all.units_rms,h2o_data_all.date_txt,h2o_data_all.telescope_ref,h2o_data_all.telescope_conf,h2o_data_all.v_step,h2o_data_all.beam,h2o_data_all.beam_maj,h2o_data_all.beam_min,h2o_data_all.beam_pa,h2o_data_all.ref,h2o_data_all.list_ref,h2o_data_all.ascii,h2o_data_all.url,h2o_data_all.image,h2o_data_all.image2,h2o_data_all.image3,h2o_data_all.descr,h2o_data_all.id,h2o_data_all.mjy_flag,h2o_data_all.rms_mjy_flag,h2o_data_all.dist,h2o_data_all.dist_parallax,h2o_data_all.date_txt,line_det,type,simbad_types_cat FROM h2o_data_all   LEFT JOIN all_objects_withmet ON h2o_data_all.grp=all_objects_withmet.group_name LEFT JOIN object_categories ON all_objects_withmet.group_name = object_categories.group_name_cat AND object_categories.tbl_cat = 'all_objects_withmet' LEFT JOIN transitions ON h2o_data_all.line=transitions."Line"  WHERE ref ilike 'SOB18' AND detected=true AND hide=false ORDER BY detected DESC,id

Display data from paper

SOB18 - Sun-sized Water Vapor Masers in Cepheus A

Interferometry data

View as list of objects

Detection table from Sobolev et al. (2018)