2026ApJ...998...33A

Query : 2026ApJ...998...33A

2026ApJ...998...33A - Astrophys. J., 998, 33 (2026/February-2)

First Results from HERA Phase II.

ABDURASHIDOVA Z., ADAMS T., AGUIRRE J.E., BAARTMAN R., BARKANA R., BERKHOUT L.M., BERNARDI G., BILLINGS T.S., BIZARRIA B.B., BOWMAN J.D., BREITMAN D., BULL P., BURBA J., BYRNE R., CAREY S., CHANDRA R.S., CHEN K.-F., CHOUDHURI S., COX T., DEBOER D.R., DE LERA ACEDO E., DEXTER M., DHANDHA J., DILLON J.S., DYNES S., EKSTEEN N., ELY J., EWALL-WICE A., FAGNONI N., FIALKOV A., FURLANETTO S.R., GALE-SIDES K., GARSDEN H., GORCE A., GORTHI D., HALDAY Z., HAZELTON B.J., HEWITT J.N., HICKISH J., HUANG T., JACOBS D.C., JOSAITIS A., KERN N.S., KERRIGAN J., KITTIWISIT P., KOLOPANIS M., LANMAN A., LA PLANTE P., LIU A., MA Y.-Z., MacMAHON D.H.E., MALAN L., MALGAS C., MALGAS K., MARERO B., MARTINOT Z.E., McBRIDE L., MESINGER A., MIROCHA J., MOHAMED-HINDS N., MOLEWA M., MORALES M.F., MUNOZ J.B., MURRAY S.G., NIKOLIC B., NUWEGELD H., PARSONS A.R., PASCUA R., PATRA N., POCHINDA S., QIN Y., RATH E., RAZAVI-GHODS N., RILEY D., ROSIE K., SANTOS M.G., SINGH S., STORER D., SWARTS H., TAN J., THELIE E., VAN WYNGAARDEN P., WILENSKY M.J., WILLIAMS P.K.G., ZHENG H. (The HERA Collaboration)

Abstract (from CDS):

We report the first upper limits on the power spectrum of 21 cm fluctuations during the Epoch of Reionization and Cosmic Dawn from Phase II of the Hydrogen Epoch of Reionization Array (HERA) experiment. HERA Phase II constitutes several significant improvements in the signal chain compared to Phase I, most notably resulting in expanded frequency bandwidth, from 50-250 MHz. In these first upper limits, we investigate a small two-week subset of the available Phase II observations, with a focus on identifying new systematic characteristics of the instrument, and establishing an analysis pipeline to account for them. We report 2σ upper limits in eight spectral bands, spanning 5.6 ≤ z ≤ 24.4 that are consistent with thermal noise at the 2σ level for k ≳ 0.6-0.9 h Mpc–1 (band dependent). Our tightest limit during Cosmic Dawn (z > 12) is 1.13 × 106 mK2 at (k = 0.55 h Mpc–1, z = 16.78), and during the EoR (5.5 < z < 12), it is 1.78 × 103 mK2 at (k = 0.70 h Mpc–1, z = 7.05). We find that mutual coupling has become our dominant systematic, leaking foreground power that strongly contaminates the low-k modes, resulting in the loss of modes from k = 0.35 to 0.55 compared to Phase I data.

Abstract Copyright: © 2026. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Reionization - Galaxy formation - Radio astronomy - Astronomy data analysis - Radio interferometers

Simbad objects: 12

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Number of rows : 12
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 3C 44 rG 01 31 21.618 +06 23 43.24   21       ~ 66 1
2 NGC 1316 rG 03 22 41.789 -37 12 29.52 9.81 9.15 8.53 7.66   ~ 1491 1
3 ESO 252-18A Sy1 05 19 49.7229323856 -45 46 43.852662732   15.73 15.77 14.85   ~ 714 0
4 M 1 SNR 05 34 31.8 +22 01 03           ~ 6516 1
5 PSR B0628-28 Psr 06 30 49.35000 -28 34 42.1000           ~ 313 1
6 MCG-02-24-007 LIN 09 18 05.66848602 -12 05 43.8060823   14.38 14.8     ~ 1077 1
7 M 87 AGN 12 30 49.42338414 +12 23 28.0436859 10.16 9.59 8.63   7.49 ~ 7815 3
8 NAME Centaurus A BLL 13 25 27.61521044 -43 01 08.8050291   8.18 6.84 6.66   ~ 4774 3
9 MCG+01-43-006 SyG 16 51 07.9886687784 +04 59 35.547131472     18.25     ~ 502 1
10 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
11 MCG+07-41-003 Bla 19 59 28.35656837 +40 44 02.0972325   16.22 15.10     ~ 2537 2
12 NAME Cas A SNR 23 23 26.0 +58 48 41     14.30     ~ 3033 1

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