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Mission Overview

Constraining star formation in M87 using deep HST UV data (M87-HST-UV)

 

Primary Investigator: Ming Sun

HLSP Authors: Prathamesh Tamhane, William Waldron, Ming Sun, Silvia Martocchia, Claudia Maraston, Alessandro Boselli, William Forman, Massimo Gaspari, Juhi Tiwari, Megan Donahue, G. Mark Voit, Tim Edge, Grant Tremblay, and Daniel Thomas

Released: 2025-11-06

Updated: 2025-11-06

Primary Reference(s):  Tamhane et al. 2025

DOI: 10.17909/1yjm-c412

Citations: See ADS Statistics

Read Me

Source Data:

 
Left: Composite color image of M87 from HST (blue: F275W, green: F606W, red: F814W). Right: Same image after subtracting the diffuse galaxy light and smoothing, with Hα emission (green) overlaid. This processing reveals compact sources and filamentary structures otherwise hidden by the galaxy’s brightness. Many yellow point sources are M87 globular clusters, while blue objects include background galaxies and young stellar sources within M87. North is up and East is left.
Figure 1: Left: Composite color image of M87 from HST (blue: F275W, green: F606W, red: F814W). Right: Same image after subtracting the diffuse galaxy light and smoothing, with Hα emission (green) overlaid. This processing reveals compact sources and filamentary structures otherwise hidden by the galaxy’s brightness. Many yellow point sources are M87 globular clusters, while blue objects include background galaxies and young stellar sources within M87. North is up and East is left.

Overview

This HLSP release presents some of the deepest HST ultraviolet imaging ever obtained, combining WFC3/UVIS F275W observations of M87 with complementary WFC3 F606W/F660N and ACS F814W mosaics. The release includes calibrated drizzled images, RMS maps, and a multi-band catalog of point sources detected in the F275W band, with photometry measured in fixed 0.05″ apertures across all filters using SExtractor in dual-image mode.

The accompanying publication (Tamhane et al. 2025) demonstrates how these data constrain M87’s star formation rate (SFR) and star formation history (SFH), revealing a very low present-day SFR (~2 × 10⁻⁵ M☉ yr⁻¹), a modest starburst ~125 Myr ago, and the presence of UV filaments aligned with Hα structures. However, the depth and quality of the UV imaging make this dataset broadly valuable for a range of studies, including the properties of globular cluster populations, searches for faint background UV galaxies, and investigations of stellar populations in dense cluster environments.

Data Products

Calibrated Science Images

The primary data products for M87-HST-UV follow this file naming convention:

hlsp_m87-hst-uv_hst_<instrument>_m87_<filter>_v1_<product-type>.fits

where:

  • <instrument> is the instrument used for observation, either "wfc3" or "acs"
  • <filter> is the name of the filter used, one of "f275w", "f606w", "f660n", or "f814w"
  • <product-type> is the type of data product, "drz-sci" for calibrated science drizzled mosaic images or "drz-rms" for RMS maps.

Photometry Catalog

In addition, there is one catalog file containing Source Detection and Photometry information, named:

hlsp_m87-hst-uv_hst_wfc3-acs_m87_multi_v1_cat.txt

The photometry was performed in fixed circular apertures of 0.05″ radius across all four bands using SExtractor in dual-image mode. The columns in this file as defined as:  

 

Column Name Description
RA_deg

Right Ascension in degrees (J2000)
Dec_deg

Declination in degrees (J2000)
F275 Aperture magnitude in F275W
F275_err Uncertainty in F275W magnitude
F606 Aperture magnitude in F606W
F606_err Uncertainty in F606W magnitude
F814 Aperture magnitude in F814W
F814_err Uncertainty in F814W magnitude

Data Access

MAST Portal and Astroquery

The M87-HST-UV data products are available in the MAST Search Portal (web-based, cross-mission search interface) and Astroquery (Python package to search for and download files from Python scripts you write).

  • In the MAST Search Portal, set the Provenance Name filter to "M87-HST-UV" in an Advanced Search to find these data. The user guide for how to search and download products using the MAST Portal is available here.
  • For Astroquery, the following example code demonstrates how to search for and download these products. This code assumes that you want to download all products from this HLSP, so you may want to consider narrowing down your search for large HLSPs (> 10 GB) or those with many individual files (> 10k). You can find more astroquery.mast tutorials here.
from astroquery.mast import Observations
# Search for all M87-HST-UV products
all_obs = Observations.query_criteria(provenance_name="m87-hst-uv")
data_products = Observations.get_product_list(all_obs)
# Print the number of data products that would be downloaded
print(len(data_products))
# Download data
Observations.download_products(data_products)

  • MAST Portal

    Link to the MAST Portal Webpage
    A web-based interface for cross-mission searches of data at MAST or the Virtual Observatory.
    Portal

  • MAST Astroquery

    Search for and download data products for this HLSP programmatically in Python.
    MAST Astroquery

Citations

Please remember to cite the appropriate paper(s) below and the DOI 10.17909/1yjm-c412 if you use these data in a published work. 

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

References

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