Starburst to Quiescent from HST/ALMA: Stars and Dust Unveil Minor Mergers in Submillimeter Galaxies at z ∼ 4.5
Research output: Contribution to journal › Journal article › Research › peer-review
Dust-enshrouded, starbursting, submillimeter galaxies (SMGs) at z ≥ 3
have been proposed as progenitors of z ≥ 2 compact quiescent galaxies
(cQGs). To test this connection, we present a detailed spatially
resolved study of the stars, dust, and stellar mass in a sample of six
submillimeter-bright starburst galaxies at z ∼ 4.5. The stellar UV
emission probed by HST is extended and irregular and shows evidence of
multiple components. Informed by HST, we deblend Spitzer/IRAC data at
rest-frame optical, finding that the systems are undergoing minor
mergers with a typical stellar mass ratio of 1:6.5. The FIR dust
continuum emission traced by ALMA locates the bulk of star formation in
extremely compact regions (median r e = 0.70 ± 0.29
kpc), and it is in all cases associated with the most massive component
of the mergers (median {log}({M}* /{M}ȯ
)=10.49+/- 0.32). We compare spatially resolved UV slope (β)
maps with the FIR dust continuum to study the infrared excess (IRX = L
IR/L UV)–β relation. The SMGs display
systematically higher IRX values than expected from the nominal trend,
demonstrating that the FIR and UV emissions are spatially disconnected.
Finally, we show that the SMGs fall on the mass–size plane at
smaller stellar masses and sizes than the cQGs at z = 2. Taking into
account the expected evolution in stellar mass and size between z = 4.5
and z = 2 due to the ongoing starburst and mergers with minor
companions, this is in agreement with a direct evolutionary connection
between the two populations.
Original language | English |
---|---|
Article number | 121 |
Journal | Astrophysical Journal |
Volume | 856 |
Issue number | 2 |
Number of pages | 18 |
ISSN | 0004-637X |
DOIs | |
Publication status | Published - 1 Apr 2018 |
- galaxies: evolution, galaxies: formation, galaxies: high-redshift, galaxies: interactions, galaxies: ISM, galaxies: starburst
Research areas
Links
- https://arxiv.org/pdf/1802.07751.pdf
Submitted manuscript
ID: 196789538