ALMA2014 LBC SVDATA

This page is currently under construction.

DO NOT USE IT.

To navigate the CASAguides pages, visit [http://casaguides.nrao.edu/ casaguides.nrao.edu ]

Overview

This casaguide describes the imaging used for the ALMA 2014 Long Baseline Campaign Science Verification data. The purpose of this campaign was to commission baseline lengths up to 15 km in preparation for this capability to be offered for Cycle 3. As part of the overall commissioning plan, five science targets were chosen to span the range of properties that would be needed to offer the capability and to demonstrate to the community both the power and caveats associated with long baseline observing. As described below the data products for four of the five targets can be dowloaded from the regional ALMA Science Portals, while the imaging scripts and salient details are provided on this page (the final target 3C138, will be released separately with other SV polarization data in the near future).

Obtaining the Data

To download the data, go to the Science Portal (SV) data page for the region closest to your location:

North America

Europe

East Asia

Choose a LBC SV science target: 13. Juno, 14. Mira, 15. HL Tau, or 16. SDP.81

There you will find gzipped tar files of the form (these files can be unpacked with the tar -xvzf command):

• Target_Band_Freq_UnCalibratedData: Raw, uncalibrated data in ALMA Science Data Model (asdm) format

• Target_Band_Freq_CalibrationScripts: Calibration scripts that go along with the UnCalibratedData. These scripts can be executed once placed in the same directory as the UnCalibratedData

• Target_Band_Freq_CalibratedData: Combined and calibrated uv-data. In the case of continuum datasets, an appropropriate amount of channel averaging has been applied to reduce the data size. Line data sets are provided at their full resolution. If self-calibration was possible, you will also find the final phase-only and amplitude tables in a subdirectory called "calibration". This gives the choice of either performing your own self-calibration or applying the supplied tables. If you are going to apply these tables, be sure to also run any flagdata commands in the imaging scripts. Note that the imaging scripts are provided on this page, not at the science portal.

• Target_Band_Freq_ReferenceImages: Final reference images with self-calibration applied where possible. For the few cases where primary beam correction is warranted these files are also provided. Images with .pbcor in the name have already been corrected. The files with .flux in the name are the primary beam images themselves and can be applied if wanted using the CASA task impbcor.

• README: Summarizes the data available for that science target.

Imaging

For each LBC SV target there is a brief description of the data. For spectral line targets the line info is given. The "description" columns are just that, they are not mean to be taken as scientific assessments but to give a sense of what the lines show.

Juno

Observations of continuum in Band 6 (233 GHz) demonstrating the ephemeris capability. The observations were taken over 60% of Juno's rotation period of 7.2 hours. The data are split into approximately 18min intervals (10min on source) and imaged and self-calibrated separately in order to prevent smearing due to the rapid rotation. The angular resolution achieved ranges from 32 x 24 mas to 42 x 36 mas (differing primarily due to the level of phase stability as the observations span the transition from night through dawn and into daytime, but changing uv-coverage also plays a role).

Mira

Observations of several SiO transitions (isotopologues and vibrational states) and continuum in Bands 3 and 6. In Band 6, one spectral window also covered a vibrationally excited H2O line. The tables below give the line tuning details. Angular resolutions achieved for the continuum data are 70 x 60 mas and 34 x 24 mas in Bands 3 (94 GHz) and 6 (231 GHz), respectively.

Mira Band 3

Line	Transition	El (K)	Rest Freq	detection
SiO v=0	2-1	2.1	86.8470	weak maser? + thermal
SiO v=1	2-1	1771	86.2434	strong maser + thermal
SiO v=2	2-1	3523	85.6405	thermal + absorption
29SiO v=0	2-1	2.1	85.7590	weak maser? + thermal

Mira Band 6

Line	Transition	El (K)	Rest Freq	detection
H30alpha	-	-	231.90093	none
H2O v2=1	5(5,0)-6(4,3)	3450.7	232.68670	thermal
SiO v=0	5-4	20.84	217.10498	weak maser? + thermal
SiO v=1	5-4	1789.8	215.59595	strong maser + thermal
SiO v=2	5-4	3541.7	214.08854	thermal + absorption
29SiO v=0	5-4	20.58	214.38576	weak maser? + thermal

HL Tau

Observations of continuum and spectral line in Band 3, and continuum only in Bands 6 & 7. Angular resolutions achieved for the continuum data are 85 x 61 mas, 35 x 22 mas, and 30 x 19 mas in Bands 3 (101.9 GHz), 6 (233.0 GHz) and 7 (343.5 GHz), respectively. It was necessary to uv-taper the spectral line data so the resulting angular resolution is coarser (up to ~1.1 arcsec).

HL Tau Band 3

Line	Transition	El (K)	Rest Freq	detection
HCN	1-0	0.0	88.63185	absorption
HCO+	1-0	0.0	89.18853	outflow, disk, absorption
CN	1-0	0.0	113.49097	absorption
12CO	1-0	0.0	115.2712	outflow, confused

Note only strongest hyperfine frequency given for HCN (3) and CN (4).

SDP.81

Observations of continuum and spectral lines in Bands 4, 6 & 7. Spectral windows covered the redshifted CO J=5-4 line in Band 4, the CO J=8-7 line and H2O, 2(0,2)-1(1,1) line in Band 6, and the CO J=10-9 line in Band 7. Angular resolutions achieved for the continuum data are 60 x 54 mas, 39 x 30 mas and 31 x 23 mas in Bands 4 (151 GHz), 6 (236 GHz), and 7 (290 GHz), respectively. It was necessary to uv-taper the spectral line data so the resulting angular resolution is coarser (up to 169 mas).

Mira Band 3

Line	Transition	El (K)	Rest Freq	detection
SiO v=0	2-1	2.1	86.8470	weak maser? + thermal