## Mission Overview

### NGC 5253 Images With Gaia DR2 Absolute Astrometry ("NGC5253-DR2")

Primary Investigator: Linda Smith

HLSP Authors: Linda Smith

Released: 2020-05-27

Updated: 2020-05-27

Primary Reference(s): Smith et al. 2020

## Overview

The blue compact dwarf galaxy NGC 5253 hosts a very young central starburst. The center contains intense radio thermal emission from a massive ultracompact H II region (or supernebula) and two massive and very young super star clusters (SSCs), which are seen at optical and infrared wavelengths. The spatial correspondence between the radio and HST images over an area of < 0".5 is very uncertain because of the limitations of Guide Star Catalog II for HST absolute astrometry. Using the Gaia Data Release 2 catalog, we improve the absolute astrometry of the HST ultraviolet, optical and infrared images by a factor of ~10 and match them to the radio observations with an accuracy of 10-20 mas. We find that the radio and optical sources do not coincide and that there are three young SSCs at the center of NGC 5253.

This High Level Science Product contains the HST images for the center of NGC 5253 re-mapped on to the Gaia DR2 reference frame. Full details of the images are given in Table 2 of Smith et al. 2020. The ACS/WFC F814W image was first mapped to the DR2 astrometry using the DrizzlePac function 'tweakreg' to an accuracy of +/- 10 mas. The smaller field of view ACS/HRC/SBC and NICMOS/NIC2 images were then aligned to the transformed ACS/WFC F814W image to accuracies of +/- 12 mas and +/- 20 mas, respectively.

## Data Products

Data file naming convention:

hlsp_ngc5253-dr2_hst_<ins>_ngc5253_<filter>_v1_drz.fits

where:

• <ins> = Instrument used, one of "acs-hrc", "acs-sbc", "acs-wfc", or "nicmos-nic2"
• <filter> = Filter used, e.g., "f330w" or "f187n"

Data file types:

 _drz.fits Drizzled science image registered to the Gaia DR2 reference frame.

## Data Access

To download the drizzled science mosaic, click on the links in the Filter column.  ACS files are ~28 MB each and NICMOS files are ~522 MB each.

Instrument

/ Camera

Drizzled Pixel Size (arcsec)

Filter

(Drizzled File)

Exposure

Time (s)

Date Of Observation GO Program
ACS/WFC 0.04 F814W 2360

2005 Dec 27

10765
ACS/SBC 0.025 F125LP 2660

2009 Mar 07

11579
ACS/HRC 0.025 F330W 1796

2006 Feb 20

10609
ACS/HRC 0.025 F435W 600

2006 Feb 20

10609
ACS/HRC 0.025 F550M 800

2006 Feb 20

10609
ACS/HRC 0.025 F658N 240

2006 Feb 20

10609
ACS/HRC 0.025 F814W 368

2006 Feb 20

10609
NICMOS/NIC2 0.04 F110W 96

1998 Jan 04

7219
NICMOS/NIC2 0.04 F160W 96

1998 Jan 04

7219
NICMOS/NIC2 0.04 F187N 256

1998 Jan 04

7219
NICMOS/NIC2 0.04 F190N 256

1998 Jan 04

7219
NICMOS/NIC2 0.04 F222M 640

1998 Jan 04

7219

## Citations

Please remember to cite the appropriate paper(s) below and the DOI if you use these data in a published work.

Note: These HLSP data products are licensed for use under CC BY 4.0.