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ALMA Central molecular zone Exploration Survey (ACES) III: Molecular line data reduction and HNCO and HCO$^{+}$ data

Daniel L. Walker, Adam Ginsburg, Ashley T. Barnes, Xing Lu, Pei-Ying Hsieh, Álvaro Sánchez-Monge, Savannah R. Gramze, Nazar Budaiev, Marc W. Pound, Jaime E. Pineda, Alyssa Bulatek, Claire Cook, Jonathan D. Henshaw, Katharina Immer, Namitha Issac, Desmond Jeff, Fu-Heng Liang, Steven N. Longmore, Elisabeth A. C. Mills, Sergio Martín, Xing Pan, Thushara G. S. Pillai, Qizhou Zhang, John Bally, Cara Battersby, Laura Colzi, Paul T. P. Ho, Izaskun Jiménez-Serra, J. M. Diederik Kruijssen, Maya A. Petkova, Mattia C. Sormani, Robin G. Tress, Jennifer Wallace, J. Armijos-Abendaño, Lucia Armillotta, N. Bijas, Rojita Buddhacharya, Laura A. Busch, Natalie O. Butterfield, Mélanie Chevance, Samuel Crowe, Ana Karla Díaz-Rodríguez, Katarzyna M. Dutkowska, Christoph Federrath, Rubén Fedriani, Pablo García, Simon C. O. Glover, Qi-Lao Gu, H Perry Hatchfield, Rebecca J. Houghton, Yue Hu, Janik Karoly, Ralf S. Klessen, Mark R. Krumholz, Farideh Mazoochi, Francisco Nogueras-Lara, Dylan Paré, Denise Riquelme-Vásquez, Víctor M. Rivilla, Miriam G. Santa-Maria, Anika Schmiedeke, Yoshiaki Sofue, Volker Tolls, Q. Daniel Wang, Gwenllian M. Williams, Fengwei Xu, Suinan Zhang

Abstract

The ALMA Central molecular zone Exploration Survey (ACES) large program has observed the inner ~ 200 pc of the Milky Way at 3 mm (Band 3) using ALMA's 12m, 7m, and Total Power arrays. With an angular resolution of ~ 2", ACES provides a contiguous, multi-scale view of the Central Molecular Zone (CMZ) via the dust continuum and a suite of molecular lines. We present an overview of the molecular line data processing for ACES and describe the first data release. We showcase the HNCO (4-3) and HCO$^{+}$ (1-0) data, which were targeted at high spectral resolution (0.2 km s$^{-1}$) to trace the kinematics of the molecular gas in the CMZ. The HNCO and HCO$^{+}$ maps are compared with previous single-dish CMZ surveys and discrete ALMA observations of CMZ clouds to demonstrate the quality of the data. We highlight the ubiquity of parsec-scale, linear absorption features traced by HCO$^{+}$. Their origin is unknown, and ACES provides the first opportunity to study these enigmatic features throughout the CMZ. We release the HNCO and HCO$^{+}$ cubes for all 45 ACES fields, along with the full cube mosaics which combine all fields into a contiguous mosaic of the CMZ. We additionally provide advanced products of these full mosaics, including integrated and peak intensity, noise, and position-velocity maps. These products provide substantial legacy value for the community, offering an unparalleled view of the physical and kinematic structure of the dense gas in the CMZ.

ALMA Central molecular zone Exploration Survey (ACES) III: Molecular line data reduction and HNCO and HCO$^{+}$ data

Abstract

The ALMA Central molecular zone Exploration Survey (ACES) large program has observed the inner ~ 200 pc of the Milky Way at 3 mm (Band 3) using ALMA's 12m, 7m, and Total Power arrays. With an angular resolution of ~ 2", ACES provides a contiguous, multi-scale view of the Central Molecular Zone (CMZ) via the dust continuum and a suite of molecular lines. We present an overview of the molecular line data processing for ACES and describe the first data release. We showcase the HNCO (4-3) and HCO (1-0) data, which were targeted at high spectral resolution (0.2 km s) to trace the kinematics of the molecular gas in the CMZ. The HNCO and HCO maps are compared with previous single-dish CMZ surveys and discrete ALMA observations of CMZ clouds to demonstrate the quality of the data. We highlight the ubiquity of parsec-scale, linear absorption features traced by HCO. Their origin is unknown, and ACES provides the first opportunity to study these enigmatic features throughout the CMZ. We release the HNCO and HCO cubes for all 45 ACES fields, along with the full cube mosaics which combine all fields into a contiguous mosaic of the CMZ. We additionally provide advanced products of these full mosaics, including integrated and peak intensity, noise, and position-velocity maps. These products provide substantial legacy value for the community, offering an unparalleled view of the physical and kinematic structure of the dense gas in the CMZ.
Paper Structure (3 sections, 1 figure, 2 tables)

This paper contains 3 sections, 1 figure, 2 tables.

Table of Contents

  1. Total Power flux recovery
  2. Joint imaging and feather vs. feather-only
  3. Feather-only integrated fluxes of all fields

Figures (1)

  • Figure B1: Comparison of the integrated fluxes between the combined 12m7mTP and the TP HNCO cubes. Integrated fluxes were calculated over a common spatial and spectral extent (Sec. \ref{['sec:comb_compare']}). The left panel shows a direct comparison of the integrated fluxes, while the right panel shows a histogram of the flux ratios (12m7mTP / TP). In both panels the dashed black line indicates perfect flux recovery, i.e. a 1-to-1 line in the left figure and a flux ratio of 1 in the right. The red dash-dot line in the right panel shows the median ratio of 1.004.