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EA: A deep near-infrared view of the Ophiuchus galaxy cluster – Coldwell
April 21, 2022 @ 12:15 pm - 12:30 pm
The Ophiuchus cluster of galaxies, the 2nd brightest X-ray cluster in the sky, has been relatively poorly studied. It is located at low latitudes in the direction of the Galactic bulge, in the Zone of Avoidance. To study the hidden galaxy population, deep near-infrared images and photometry from the VISTA Variables in the Vía Láctea eXtended survey (VVVX) were used. Adopting the Galdeano et al. (2021) criteria to select the galaxies among the foreground sources we identified 537 visually confirmed galaxy member candidates of the Ophiuchus cluster up to 2 Mpc from the cD galaxy. This represents 7 times more galaxies than obtained in previous works. Furthermore, we classified the galaxy candidates following the morphological features. We found that the proportion of Ellipticals reaches more than 60% in the central region of the cluster and the fraction of Spirals is lower than the 20% remaining almost constant throughout the cluster. Moreover, from the red sequence, we verified the sample of galaxy member candidates. We compared the integrated number of galaxies expected up to the Ophiuchus redshift, finding that the value derived from the mock catalog towards an overdense region is in agreement with the galaxy excess of the central zone of the cluster. Our investigation of the hidden population of Ophiuchus galaxies underscores the importance of this cluster as a prime target for future photometric and spectroscopic studies. Moreover, the results of this work highlight the potential of VVVX survey to study extragalactic objects in the Zone of Avoidance.