Observations of the Corona Borealis supercluster with the superextended Very Small Array: further constraints on the nature of the non-Gaussian CMB cold spot

Abstract

We present interferometric imaging at 33 GHz, with the new superextended configuration of the Very Small Array (VSA), of a very deep decrement in the cosmic microwave background (CMB) temperature. This decrement is located in the direction of the Corona Borealis supercluster, at a position with no known galaxy clusters, and was discovered by a previous VSA survey (Genova-Santos et al.). A total area of 3 sq.deg. has now been imaged, with an angular resolution of 7 arcmin and a flux sensitivity of 5 mJy/beam. These observations confirm the presence of this strong and resolved negative spot at -41+/-5 mJy/beam (-258+/-29 muK), with a signal to noise level of 8. This structure is also present in the WMAP 5-year data. The temperature of the W-band (94 GHz) data at the position of the decrement agrees within 1.2-sigma with that observed by the VSA at 33 GHz, and within 0.2-sigma with the Sunyaev-Zel'dovich (SZ) spectrum. Our analyses show that it is a non-Gaussian feature in the CMB at a level of 4.8-sigma. The probability of finding such a deviation or larger in CMB Gaussian simulations is only 0.19 per cent. Therefore, an explanation other than primordial CMB is required. We have considered the possibility of an SZ effect generated in a diffuse, extended warm/hot gas distribution. This hypothesis is especially relevant, as the presence of such structures, if confirmed, could provide the location for a significant fraction of the missing baryons in the Local Universe.

Submitted to MNRAS

References in corpus (12)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Likelihoods and Parameters from the WMAP data
• Where Are the Baryons? II: Feedback Effects
• Detection of the ISW and SZ effects from the CMB-Galaxy correlation
• A Cosmic Microwave Background feature consistent with a cosmic texture
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP)Observations: Beam Maps and Window Functions
• Origin of the Counter-Rotating Gas in NGC 1596
• The thermal Sunyaev-Zel'dovich Signature of Baryons in the Local Universe
• Kinematic Sunyaev-Zeldovich Cosmic Microwave Background Temperature Anisotropies Generated by Gas in Cosmic Structures
• Non-Gaussianity in the Very Small Array CMB maps with Smooth-Goodness-of-fit tests
• Millimetric observation of the SZ effect in the Corona Borealis supercluster
• On the Rees-Sciama effect: maps and statistics

Cited by in corpus (13)

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• Follow-up observations at 16 and 33 GHz of extragalactic sources from WMAP 3-year data: I - Spectral properties
• Some statistical remarks on the Giant GRB Ring
• The Corona Borealis supercluster: connectivity, collapse, and evolution
• The contribution of the kinematic Sunyaev-Zel'dovich Effect from the Warm Hot Intergalactic Medium to the Five-Year WMAP Data
• The Sunyaev-Zeldovich effect in superclusters of galaxies using gasdynamical simulations: the case of Corona Borealis
• Textures and Semi-Local Strings in SUSY Hybrid Inflation
• The spatial distribution of galaxies within the CMB cold spot in the Corona Borealis supercluster
• Constraints on the Sunyaev-Zel'dovich signal from the Warm Hot Intergalactic Medium from WMAP and SPT data
• A study of the galaxy redshift distribution toward the cosmic microwave background cold spot in the Corona Borealis supercluster