HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization

HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization. Collaboration, T. H., Abdurashidova, Z., Aguirre, J. E., Alexander, P., Ali, Z., Balfour, Y., Barkana, R., Beardsley, A., Bernardi, G., Billings, T., Bowman, J., Bradley, R., Bull, P., Burba, J., Carey, S., Carilli, C., Cheng, C., DeBoer, D., Dexter, M., Acedo, E. d. L., Dillon, J., Ely, J., Ewall-Wice, A., Fagnoni, N., Fialkov, A., Fritz, R., Furlanetto, S., Gale-Sides, K., Glendenning, B., Gorthi, D., Greig, B., Grobbelaar, J., Halday, Z., Hazelton, B., Heimersheim, S., Hewitt, J., Hickish, J., Jacobs, D., Julius, A., Kern, N., Kerrigan, J., Kittiwisit, P., Kohn, S., Kolopanis, M., Lanman, A., La Plante, P., Lekalake, T., Lewis, D., Liu, A., Ma, Y., MacMahon, D., Malan, L., Malgas, C., Maree, M., Martinot, Z., Matsetela, E., Mesinger, A., Mirocha, J., Molewa, M., Morales, M., Mosiane, T., Munoz, J., Murray, S., Neben, A., Nikolic, B., Nunhokee, C. D., Parsons, A., Patra, N., Pieterse, S., Pober, J., Qin, Y., Razavi-Ghods, N., Reis, I., Ringuette, J., Robnett, J., Rosie, K., Santos, M., Sikder, S., Sims, P., Smith, C., Syce, A., Thyagarajan, N., Williams, P., & Zheng, H. 2021. cite arxiv:2108.07282Comment: 40 pages, 19 figures, submitted to ApJ

Paper abstract bibtex

Recently, the Hydrogen Epoch of Reionization Array (HERA) collaboration has produced the experiment's first upper limits on the power spectrum of 21-cm fluctuations at z 8 and 10. Here, we use several independent theoretical models to infer constraints on the intergalactic medium (IGM) and galaxies during the epoch of reionization (EoR) from these limits. We find that the IGM must have been heated above the adiabatic cooling threshold by z 8, independent of uncertainties about the IGM ionization state and the nature of the radio background. Combining HERA limits with galaxy and EoR observations constrains the spin temperature of the z 8 neutral IGM to 27 K < T_S < 630 K (2.3 K < T_S < 640 K) at 68% (95%) confidence. They therefore also place a lower bound on X-ray heating, a previously unconstrained aspects of early galaxies. For example, if the CMB dominates the z 8 radio background, the new HERA limits imply that the first galaxies produced X-rays more efficiently than local ones (with soft band X-ray luminosities per star formation rate constrained to L_X/SFR = 10^40.2, 10^41.9 erg/s/(M_sun/yr) at 68% confidence), consistent with expectations of X-ray binaries in low-metallicity environments. The z 10 limits require even earlier heating if dark-matter interactions (e.g., through millicharges) cool down the hydrogen gas. Using a model in which an extra radio background is produced by galaxies, we rule out (at 95% confidence) the combination of high radio and low X-ray luminosities of L_r,ν/SFR > 3.9 x 10^24 W/Hz/(M_sun/yr) and L_X/SFR<10^40 erg/s/(M_sun/yr). The new HERA upper limits neither support nor disfavor a cosmological interpretation of the recent EDGES detection. The analysis framework described here provides a foundation for the interpretation of future HERA results.

@misc{collaboration2021phase,
  abstract = {Recently, the Hydrogen Epoch of Reionization Array (HERA) collaboration has
produced the experiment's first upper limits on the power spectrum of 21-cm
fluctuations at z~8 and 10. Here, we use several independent theoretical models
to infer constraints on the intergalactic medium (IGM) and galaxies during the
epoch of reionization (EoR) from these limits. We find that the IGM must have
been heated above the adiabatic cooling threshold by z~8, independent of
uncertainties about the IGM ionization state and the nature of the radio
background. Combining HERA limits with galaxy and EoR observations constrains
the spin temperature of the z~8 neutral IGM to 27 K < T_S < 630 K (2.3 K < T_S
< 640 K) at 68% (95%) confidence. They therefore also place a lower bound on
X-ray heating, a previously unconstrained aspects of early galaxies. For
example, if the CMB dominates the z~8 radio background, the new HERA limits
imply that the first galaxies produced X-rays more efficiently than local ones
(with soft band X-ray luminosities per star formation rate constrained to
L_X/SFR = { 10^40.2, 10^41.9 } erg/s/(M_sun/yr) at 68% confidence), consistent
with expectations of X-ray binaries in low-metallicity environments. The z~10
limits require even earlier heating if dark-matter interactions (e.g., through
millicharges) cool down the hydrogen gas. Using a model in which an extra radio
background is produced by galaxies, we rule out (at 95% confidence) the
combination of high radio and low X-ray luminosities of L_{r,\nu}/SFR > 3.9 x
10^24 W/Hz/(M_sun/yr) and L_X/SFR<10^40 erg/s/(M_sun/yr). The new HERA upper
limits neither support nor disfavor a cosmological interpretation of the recent
EDGES detection. The analysis framework described here provides a foundation
for the interpretation of future HERA results.},
  added-at = {2021-08-18T06:17:22.000+0200},
  author = {Collaboration, The HERA and Abdurashidova, Zara and Aguirre, James E. and Alexander, Paul and Ali, Zaki and Balfour, Yanga and Barkana, Rennan and Beardsley, Adam and Bernardi, Gianni and Billings, Tashalee and Bowman, Judd and Bradley, Richard and Bull, Phillip and Burba, Jacob and Carey, Steven and Carilli, Christopher and Cheng, Carina and DeBoer, David and Dexter, Matthew and Acedo, Eloy de Lera and Dillon, Joshua and Ely, John and Ewall-Wice, Aaron and Fagnoni, Nicolas and Fialkov, Anastasia and Fritz, Randall and Furlanetto, Steven and Gale-Sides, Kingsley and Glendenning, Brian and Gorthi, Deepthi and Greig, Bradley and Grobbelaar, Jasper and Halday, Ziyaad and Hazelton, Bryna and Heimersheim, Stefan and Hewitt, Jacqueline and Hickish, Jack and Jacobs, Daniel and Julius, Austin and Kern, Nicholas and Kerrigan, Joshua and Kittiwisit, Piyanat and Kohn, Saul and Kolopanis, Matthew and Lanman, Adam and La Plante, Paul and Lekalake, Telalo and Lewis, David and Liu, Adrian and Ma, Yin-Zhe and MacMahon, David and Malan, Lourence and Malgas, Cresshim and Maree, Matthys and Martinot, Zachary and Matsetela, Eunice and Mesinger, Andrei and Mirocha, Jordan and Molewa, Mathakane and Morales, Miguel and Mosiane, Tshegofalang and Munoz, Julian and Murray, Steven and Neben, Abraham and Nikolic, Bojan and Nunhokee, Chuneeta Devi and Parsons, Aaron and Patra, Nipanjana and Pieterse, Samantha and Pober, Jonathan and Qin, Yuxiang and Razavi-Ghods, N. and Reis, Itamar and Ringuette, Jon and Robnett, James and Rosie, Kathryn and Santos, Mario and Sikder, Sudipta and Sims, Peter and Smith, Craig and Syce, Angelo and Thyagarajan, Nithyanandan and Williams, Peter and Zheng, Haoxuan},
  biburl = {https://www.bibsonomy.org/bibtex/21f83b9d410b9b1d9315f185c0a3cf44f/gpkulkarni},
  description = {HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization},
  interhash = {9e3d677386fbb19d6115213d65ec3d8d},
  intrahash = {1f83b9d410b9b1d9315f185c0a3cf44f},
  keywords = {library},
  note = {cite arxiv:2108.07282Comment: 40 pages, 19 figures, submitted to ApJ},
  timestamp = {2021-08-18T06:17:22.000+0200},
  title = {HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on
  Astrophysics and Cosmology During the Epoch of Reionization},
  url = {http://arxiv.org/abs/2108.07282},
  year = 2021
}

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