Probing Star Formation at Low Metallicity: The Radio Emission of Super Star Clusters in SBS0335-052

Abstract

We present high-resolution radio continuum observations of the nascent starburst in the metal-poor galaxy SBS 0335-052. These radio data were taken with the Very Large Array and include observations at 0.7cm, 1.3cm, 2cm, 3.6cm, and 6cm. These observations enable us to probe the thermal radio nebulae associated with the extremely young star-forming regions in this galaxy. Two discrete and luminous star-forming regions are detected in the south of the galaxy that appear to be associated with massive star clusters previously identified at optical wavelengths. However, the remaining optically-identified massive star clusters are not clearly associated with radio emission (either thermal or non-thermal) down to the sensitivity limits of these radio data. The spectral energy distributions of the two radio-detected clusters are consistent with being purely thermal, and the entire region has an inferred ionizing flux of ~1.2 x 10^ 53 s^-1, which is equivalent to ~12,000 "typical" O-type stars (type O7.5 V). The observations presented here have resolved out a significant contribution from diffuse non-thermal emission detected previously, implying a previous episode of significant star formation. The current star formation rate (SFR) for this southern region alone is ~1.3 M_sun yr^-1, or ~ 23M_sun yr^-1 kpc^-2. This SFR derived from thermal radio emission also suggests that previous optical recombination line studies are not detecting a significant fraction of the current star formation in SBS 0335-052. From model fits to the radio spectral energy distribution, we infer a global mean density in the two youngest clusters of n_e > 10^3-10^4 cm^-3. In addition, a comparison between the compact and diffuse radio emission indicates that up to ~50% of the ionizing flux could be leaking out of the compact HII regions.

accepted AJ, 14 pages, 5 figures

References in corpus (4)

• A New View of the Super Star Clusters in the Low-Metallicity Galaxy SBS 0335-052
• PAH Strength and the Interstellar Radiation Field around the Massive Young Cluster NGC3603
• Oxygen abundance variations in the system of the two blue compact dwarf galaxies SBS 0335-052E and SBS 0335-052W
• Time evolution of the radio continuum of young starbursts: The importance of synchrotron emission

Cited by in corpus (15)

• A Candidate Massive Black Hole in the Low-metallicity Dwarf Galaxy Pair Mrk 709
• Coevolution of metallicity and star formation in galaxies to z=3.7: I. A fundamental plane
• The Physical Conditions in a Pre Super Star Cluster Molecular Cloud in the Antennae Galaxies
• JADES -- The Rosetta Stone of JWST-discovered AGN: deciphering the intriguing nature of early AGN
• Looking for obscured young star clusters in NCG 1313
• Stars and gas in the most metal-poor galaxies I: COS and MUSE observations of SBS 0335-052E
• Outflows, Shocks and Coronal Line Emission in a Radio-Selected AGN in a Dwarf Galaxy
• Embedded Young Massive Star Clusters in the Antennae Merger
• The radio properties of the JWST-discovered AGN
• A $\sim$15 kpc outflow cone piercing through the halo of the blue compact metal-poor galaxy SBS0335-052
• VLA and ATCA Search for Natal Star Clusters in Nearby Star-Forming Galaxies
• Dust Buried Compact Sources in the Dwarf Galaxy NGC 4449
• Exploring the mysterious high-ionization source powering [Ne V] in high-z analog SBS0335-052 E with JWST/MIRI
• Nowhere Left to Hide: Uncovering All of the Massive Young Embedded Star Clusters in the Antennae with JWST
• When Stars Mimic Monsters: Spectral Evidence for an $\eta$ Carinae-like Giant Eruption in SBS 0335$-$052 E