Service Observing

# Service Observing

## NRAO Initial Observation of the Type 1a Supernova in M82

A new type 1a supernova in the nearby starburst galaxy M82 was discovered on Jan 22, 2014, by students at University College, London.  Initial radio observations have been performed using the VLA on Jan 23 and Jan 24, 2014, as a community service, under project code TOBS0008.  The observations comprised one 2-hr scheduling block observing at 5.5 and 22 GHz, and an additional 2-hr scheduling block observing only at 5.5 GHz (Jan 23); a 4-hr scheduling block at 5.5 GHz was observed on Jan 24.  The raw archive data are available for download from the NRAO archive.  The calibrated visibility data are available via anonymous ftp as tarred CASA measurement sets:

ftp ftp.aoc.nrao.educd e2earchive/TOBS0008

To obtain the calibrated 22 GHz data (includes spectral averaging to reduce dataset size):

get SN2014J_K.tar

To obtain the calibrated 5.5 GHz data:

get SN2014J_C1.target SN2014J_C2.target SN2014J_C3.tar

A FITS format image derived from the combined 5.5 GHz data is also available at the same location (NB: this image has NOT been corrected for the response of the primary beam; it should NOT be used to derive flux densities at any location other than at the center of the image):

get SN2014J_Cband.fits

## NRAO Monitoring of the Galactic Center/G2 Cloud Encounter

NRAO has now completed its monitoring observations of the Galactic Center region through the encounter with the G2 cloud (see the October 2012 NRAO eNews).  The VLA monitoring data have been obtained under project code TOBS0006, and the raw data are available through the NRAO Archive.  Photometry, calibrated visibility data, and some images are posted below.

2014 May 31, VLA A-configuration

The emission detected in A configuration from the Galactic Center region in early 2014 looks marginally curved and may be interpreted as a slight flattening at the lower frequency end (see the A-configuration flux density baseline images from October 14, 2012).

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyCalibrated uv-data (CASA MS format)

2014 April 26, VLA A-configuration

The emission detected in A configuration from the Galactic Center region in early 2014 looks marginally curved and may be interpreted as a slight flattening at the lower frequency end (see the A-configuration flux density baseline images from October 14, 2012). However, with only an upper limit available in S band, at this stage this is still not significant.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyCalibrated uv-data (CASA MS format)
3.0 0.75 (upper limit)

2014 March 22, VLA A-configuration

The emission detected in A configuration from the Galactic Center region in early 2014 looks marginally curved and may be interpreted as a slight flattening at the lower frequency end (see the A-configuration flux density baseline images from October 14, 2012). However, at this stage this is still not significant because of an inconclusive measurement at 1.5 GHz, where only an upper limit is available for the flux density of SgrA*.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyCalibrated uv-data (CASA MS format)
1.5 0.68 (upper limit)

2014 February 15, VLA A-configuration

The emission detected in A configuration from the Galactic Center region in early 2014 looks marginally curved and may be interpreted as a slight flattening at the lower frequency end (see the A-configuration flux density baseline images from October 14, 2012). However, at this stage this is still not significant because of an inconclusive measurement at 1.5 GHz, where only an upper limit is available for the flux density of SgrA*.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyCalibrated uv-data (CASA MS format)
1.5 0.67 (upper limit)
10.0 0.86
1.0
14.0 0.96
0.5

2013 December 29, VLA B-configuration

Only the lowest frequency emission detected in B configuration from the Galactic Center region is still somewhat confused (see the A-configuration flux density baseline images from October 14, 2012). Only upper limits are available for the flux density of SgrA* at the lowest frequencies. Flux densities have been derived using Briggs (robust=0) weighting.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyCalibrated uv-data (CASA MS format)
1.5 3.9 (upper limit)
3.0 0.7 (upper limit)
10.0 0.72
3.9
14.0 0.85
3.1

2013 November 29, VLA B-configuration

Only the lowest frequency emission detected in B configuration from the Galactic Center region is still somewhat confused (see the A-configuration flux density baseline images from October 14, 2012). Only upper limits are available for the flux density of SgrA* at the lowest frequencies. Flux densities have been derived using Briggs (robust=0) weighting.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyCalibrated uv-data (CASA MS format)
1.5 1.5 (upper limit)
3.0 1.0 (upper limit)
10.0 0.96
0.6
14.0 1.15
1.1

2013 October 26, VLA B-configuration

Only the lowest frequency emission detected in B configuration from the Galactic Center region is still somewhat confused (see the A-configuration flux density baseline images from October 14, 2012). Only upper limits are available for the flux density of SgrA* at the lowest frequencies. Flux densities have been derived using Briggs (robust=0) weighting.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyCalibrated uv-data (CASA MS format)
1.5 1.6 (upper limit)
3.0 0.89 (upper limit)
10.0 0.91
1.3
14.0 1.05
1.2

2013 September 18, VLA CnB-configuration

The emission from the Galactic Center region is still somewhat confused in the CnB-configuration, especially at low frequencies (see the A-configuration images from October 14, 2012).  Flux densities have been derived from images using inner uv-cutoffs, and Briggs (robust=0) weighting.  Only upper limits are available for the flux density of SgrA* at the lower frequencies.  The weather was poor during this epoch, with light rain during the  observation.  The uncertainty on the absolute flux density at the high frequencies is therefore larger than at other epochs.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyCalibrated uv-data (CASA MS format)
1.5 4.0 (upper limit)
3.0 1.99 (upper limit)
5.5 1.39 (upper limit)
10.0 1.039
1.8
14.0 1.234
1.3

2013 August 08, VLA C-configuration

The emission from the Galactic Center region is still somewhat confused in the C-configuration, especially at low frequencies (see the A-configuration images from October 14, 2012).  Flux densities have been derived from images using inner uv-cutoffs, and Briggs (robust=0) weighting.  Only upper limits are available for the flux density of SgrA* at the lower frequencies.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyCalibrated uv-data (CASA MS format)
1.5 10.1 (upper limit)
3.0 2.38 (upper limit)
5.5 1.50 (upper limit)
10.0 1.044
7.1
14.0 1.180
4.8

2013 June 09, VLA C-configuration

The emission from the Galactic Center region is still somewhat confused in the C-configuration, especially at low frequencies (see the A-configuration images from October 14, 2012).  Flux densities have been derived from images using inner uv-cutoffs, and Briggs (robust=0) weighting.  Only upper limits are available for the flux density of SgrA* at the lower frequencies.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyCalibrated uv-data (CASA MS format)
1.5 15.0 (upper limit)
3.0 1.79 (upper limit)
5.5 1.21 (upper limit)
10.0 0.964
2.1
14.0 1.086
2.5

2013 April 26, VLA D-configuration

The emission from the Galactic Center region is very confused in the D-configuration, especially at low frequencies (see the A-configuration images from October 14, 2012).  Flux densities have been derived from images using inner uv-cutoffs, and Briggs (robust=0) weighting.  Only upper limits are available for the flux density of SgrA* at the lower frequencies.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyCalibrated uv-data (CASA MS format)

2013 March 23, VLA D-configuration

The emission from the Galactic Center region is very confused in the D-configuration, especially at low frequencies (see the A-configuration images from October 14, 2012).  Flux densities have been derived from images using inner uv-cutoffs, and Briggs (robust=0) weighting.  Only upper limits are available for the flux density of SgrA* at the lower frequencies.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyCalibrated uv-data (CASA MS format)

2013 February 18, VLA D-configuration

The emission from the Galactic Center region is very confused in the D-configuration, especially at low frequencies (see the A-configuration images from October 14, 2012).  Flux densities have been derived from images using inner uv-cutoffs, and Briggs (robust=0) weighting.  Only upper limits are available for the flux density of SgrA* at the lower frequencies.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)
Absolute calibration uncertainty Calibrated uv-data (CASA MS format)

2012 December 22, VLA A-configuration

For images, please see the results from October 14, 2012.

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertainty Calibrated uv-data (CASA MS format)

2012 October 14, VLA A-configuration

Frequency (GHz)Integrated flux density (Jy)Statistical error (mJy)Absolute calibration uncertaintyImage FITS image

Calibrated uv-data (CASA MS format)

1.5 0.660 3.2 10%

3.0 0.750 0.58 10%

5.5 0.870 0.54 10%

10.0 0.983 0.36 10%

14.0 1.090 0.34 10%

21.2 1.216 0.44 10%