Science at IPAC

Our community of active researchers is key to the strategic development and execution of all programs supported by IPAC. IPAC scientific staff are engaged in forefront research spanning a broad range of fields in astrophysics and planetary sciences. Areas of special focus include exoplanets; dark energy and cosmology; star formation and galaxy evolution; asteroids and the solar system; and the area in which IPAC has provided leadership for over three decades -- exploration of the infrared and sub-mm universe.

Latest Research Publications

Enhanced Subkiloparsec-scale Star Formation: Results from a JWST Size Analysis of 341 Galaxies at 5 < z < 14

March 2024 • Morishita, Takahiro • Stiavelli, Massimo • Chary, Ranga-Ram • et al.

We present a comprehensive search and analysis of high-redshift galaxies in a suite of nine public JWST extragalactic fields taken in Cycle 1, covering a total effective search area of $\sim 358\,{\mathrm{arcmin}}^{2}$ . Through conservative (8σ) photometric selection, we identify 341 galaxies at 5 < z < 14, with 109 having spectroscopic redshift measurements from the literature, including recent JWST NIRSpec observations. Our regression analysis reveals that the rest-frame UV size–stellar mass relation follows ${R}_{\mathrm{eff}}\propto {M}_{* }^{0.19\pm 0.03}$ , similar to that of star-forming galaxies at z ∼ 3, but scaled down in size by ∼0.7 dex. We find a much slower rate for the average size evolution over the redshift range, R _eff ∝ (1 + z)^‑0.4±0.2,...

Takahiro Morishita

Assistant Scientist

Research Interests: Galaxies

Stellar Population Properties in the Stellar Streams around SPRC047

February 2024 • Laine, Seppo • Martínez-Delgado, David • Webb, Kristi A. • et al.

We have investigated the properties (e.g., age, metallicity) of the stellar populations of a ringlike tidal stellar stream (or streams) around the edge-on galaxy SPRC047 (z = 0.031) using spectral energy distribution (SED) fits to integrated broadband aperture flux densities. We used visual images in six different bands and Spitzer/IRAC 3.6 μm data. We have attempted to derive best-fit stellar population parameters (metallicity, age) in three noncontiguous segments of the stream. Due to the very low surface brightness of the stream, we have performed a deconvolution with a Richardson–Lucy–type algorithm of the low spatial resolution 3.6 μm IRAC image, thereby reducing the effect of the point-spread function aliased emission from the bright edge-on central galaxy at the locations of our...

Seppo Laine

Associate Scientist

Research Interests: My main scientific interests include 1) visible light, infrared and radio wavelength observations of extended structures around nearby galaxies, specifically stellar streams, 2) observational nearby galaxy structure, dynamics and...

The POKEMON Speckle Survey of Nearby M Dwarfs. II. Observations of 1125 Targets

February 2024 • Clark, Catherine A. • van Belle, Gerard T. • Horch, Elliott P. • et al.

Stellar multiplicity is correlated with many stellar properties, yet multiplicity measurements have proven difficult for the M dwarfs-the most common type of star in our galaxy-due to their faintness and the fact that a reasonably complete inventory of later M dwarfs did not exist until recently. We have therefore carried out the Pervasive Overview of "Kompanions" of Every M dwarf in Our Neighborhood (POKEMON) survey, which made use of the Differential Speckle Survey Instrument on the 4.3 m Lowell Discovery Telescope, along with the NN-EXPLORE Exoplanet Stellar Speckle Imager on the 3.5 m WIYN telescope. The POKEMON sample is volume limited from M0V through M9V out to 15 pc, with additional brighter targets at larger distances. In total, 1125 targets were observed. New discoveries were...