MAGAZ3NE: Massive, Extremely Dusty Galaxies at z ∼ 2 Lead to Photometric Overestimation of Number Densities of the Most Massive Galaxies at 3 < z < 4*
Abstract We present rest-frame optical spectra from Keck/MOSFIRE and Keck/NIRES of 16 candidate ultramassive galaxies targeted as part of the Massive Ancient Galaxies at z > 3 Near-Infrared Survey (MAGAZ3NE). These candidates were selected to have photometric redshifts 3 ≲ z phot <4, photometric stellar masses <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="normal">log</mml:mi> </mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>∗</mml:mo> </mml:mrow> </mml:msub> <mml:mrow> <mml:mo>/</mml:mo> </mml:mrow> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> <mml:mo stretchy="false">)</mml:mo> </mml:math> > 11.7, and well-sampled photometric spectral energy distributions (SEDs) from the UltraVISTA and VIDEO surveys. In contrast to previous spectroscopic observations of blue star-forming and poststarburst ultramassive galaxies, candidates in this sample have very red SEDs implying significant dust attenuation, old stellar ages, and/or active galactic nuclei (AGN). Of these galaxies, eight are revealed to be heavily dust-obscured 2.0 < z < 2.7 galaxies with strong emission lines, some showing broad features indicative of AGN, three are Type I AGN hosts at z > 3, one is a z ∼ 1.2 dusty galaxy, and four galaxies do not have a confirmed spectroscopic redshift. In fact, none of the sample has ∣ z spec − z phot ∣ < 0.5, suggesting difficulties for photometric redshift programs in fitting similarly red SEDs. The prevalence of these red interloper galaxies suggests that the number densities of high-mass galaxies are overestimated at z ≳ 3 in large photometric surveys, helping to resolve the “impossibly early galaxy problem” and leading to much better agreement with cosmological galaxy simulations. A more complete spectroscopic survey of ultramassive galaxies is required to pin down the uncertainties on their number densities in the early Universe.
Authors
- Ian McConachie (ORCID: https://orcid.org/0000-0002-2446-8770)
- Joey Braspenning
- Joop Schaye (ORCID: https://orcid.org/0000-0002-0668-5560)
- Ben Forrest (ORCID: https://orcid.org/0000-0001-6003-0541)
- Danilo Marchesini (ORCID: https://orcid.org/0000-0001-9002-3502)
- Fabio Fontanot (ORCID: https://orcid.org/0000-0003-4744-0188)
- Stephanie M. Urbano Stawinski (ORCID: https://orcid.org/0000-0001-8169-7249)
- Michael C. Cooper (ORCID: https://orcid.org/0000-0003-1371-6019)
- Dylan Nelson (ORCID: https://orcid.org/0000-0001-8421-5890)
- Adam Muzzin (ORCID: https://orcid.org/0000-0002-9330-9108)
- Mauro Stefanon (ORCID: https://orcid.org/0000-0001-7768-5309)
- Gillian Wilson (ORCID: https://orcid.org/0000-0002-6572-7089)
- Marianna Annunziatella (ORCID: https://orcid.org/0000-0002-8053-8040)
- Lizhi Xie (ORCID: https://orcid.org/0000-0003-3864-068X)
- Z. Cemile Marsan (ORCID: https://orcid.org/0000-0002-7248-1566)
- Percy Gómez (ORCID: https://orcid.org/0000-0003-0408-9850)
- Wenjun Chang (ORCID: https://orcid.org/0000-0003-2144-2943)
- Annalisa Pillepich (ORCID: https://orcid.org/0000-0003-1065-9274)
- Michaela Hirschmann (ORCID: https://orcid.org/0000-0002-3301-3321)
- G. De Lucia (ORCID: https://orcid.org/0000-0002-6220-9104)
Institutions
- University of California, Riverside (US)
- Leiden University (NL)
- Tufts University (US)
- Tianjin Normal University (CN)
- University of California, Merced (US)
- Universitat de València (ES)
- York University (CA)
- University of California, Irvine (US)
- Heidelberg University (DE)
- W.M. Keck Observatory (US)
- Trieste Astronomical Observatory (IT)
- Max Planck Institute for Astronomy (DE)
- Centro de Astrobiología (ES)
- Institute for Fundamental Physics of the Universe (IT)
- Instituto de Física de Cantabria (ES)
- École Polytechnique Fédérale de Lausanne (CH)
- University of California, Davis (US)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2024-12-01
- DOI
- https://doi.org/10.3847/1538-4357/ad8b1c
- Citations
- 5
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 1.66
Funders
- National Science Foundation
- National Aeronautics and Space Administration
- W. M. Keck Foundation
- Space Telescope Science Institute
- Durham University
- Deutsche Forschungsgemeinschaft
- Science and Technology Facilities Council