Deep Photometry of Suspected Gravitational Lensing Events: Potential Detection of a Cosmic String (2309.11831v1)

Abstract: Cosmic strings (CS) are one-dimensional cosmological-size objects predicted in realistic models of the early Universe. Analysis of the cosmic microwave background (CMB) anisotropy data from the Wilkinson Microwave Anisotropy Probe (WMAP) and Planck surveys revealed several CS candidates. One of the candidates, CSc-1, was found to be most reliable because of the statistically significant chains of gravitational lensing (GL) candidates in its field. We observed the brightest of the objects in the CSc-1 field, a galaxy pair SDSSJ110429.61+233150.3. The significant correlation between the spectra of the two components indicates the possible GL nature of the pair. Our simulations of observational data in the CSc-1 field shows that a large number of pairs can be explained by the complex geometry of the CS. Simulations of the SDSSJ110429 galaxy pair has shown that the observed angle between the components of the pair can be explained if the CS is strongly inclined and, possibly, bent in the image plane. In our preliminary data, we also detected the sign of the sharp isophotal edge in one image, which along with CMB and spectral data strongly suggests the possibility of a CS detection.

• The paper demonstrates that statistical analysis of gravitational lensing events can identify cosmic string candidates.
• It employs dual methodologies, including spectroscopic alignment and photometric correlation, to validate lensing signatures in galaxy pairs.
• These findings support enhanced survey techniques for detecting topological defects and advancing our understanding of early universe dynamics.

Deep Photometry of Suspected Gravitational Lensing Events: Potential Detection of a Cosmic String

The paper presented in this paper focuses on the exploration of cosmic strings (CS), which are hypothesized as one-dimensional cosmological-scale entities that emerged in the early universe as postulated by current cosmological theories. Despite being theoretically predicted, these entities remain elusive in terms of empirical confirmation. This paper addresses a compelling case for the detection of a cosmic string candidate, designated as CSc-1, identified from the analysis of Cosmic Microwave Background (CMB) anisotropy data obtained from the WMAP and Planck satellite surveys.

A remarkable aspect of the investigation is the deployment of a dual-methodological approach. Primarily, it relies on the statistical analysis of gravitational lensing (GL) event chains, specifically galaxy pairs, suggesting CS involvement. Approximately 30 objects in the CSc-1 field were detected as potential GL images based on SDSS survey data. The selection criteria for a reliable CS candidate hinged upon these occurrences of gravitational lensing, which are potentially indicative of a complex geometry associated with a cosmic string.

A pivotal case paper within this research is the galaxy pair SDSSJ110429.61+233150.3 (henceforth, SDSSJ110429-A,B), located in the CSc-1 field. The spectroscopic and photometric investigations employed the Himalayan Faint Object Spectrograph and Camera (HFOSC) at the Indian Astronomical Observatory. Within this observational framework, the galaxies SDSSJ110429-A,B exhibited aligned spectral features, a haLLMark suggestive of gravitational lensing due to identical source origins viewed through a gravitational lens, presumably the cosmic string.

Significant numerical results are observed in the calculated correlation coefficients between the smoothed spectra of the galaxy components, revealing significant alignment and correlation, furthering the lensing hypothesis. The interpretation of spectral lines via statistical metrics such as the χ² goodness-of-fit test yielded results in favor of identical spectral characteristics. Such findings lend a strong argument for gravitational lensing, postulating the positioned cosmic string's role in image duplication.

Further, the research engages in modeling efforts to account for the gravitational lensing mechanics when the cosmic string is inclined relative to the image plane, providing insights into the cosmic string's angular deficit. These geometrical considerations and adjustments to model parameters depict scenarios accommodating the observed characteristics of the galaxy pair SDSSJ110429-A,B, including the potential bend of the cosmic string in the image plane.

From a theoretical perspective, this research builds upon existing frameworks by delivering empirical tests and simulations reinforcing the hypothesis of cosmic string detection. The paper underscores important implications for ongoing and future astronomical survey methodologies. Specifically, it highlights the need for surveys with high signal-to-noise ratios, broad multi-band coverage, and excellent photometric accuracy, to facilitate the detection of such elusive cosmic phenomena.

Looking forward, this research sets a precedent for enhanced exploration of topological defects in the universe through advanced observational strategies and modeling efforts. Potential future developments in this domain could involve leveraging larger telescopes, such as the upcoming generation of Extremely Large Telescopes (ELT), which could dramatically improve the resolution and depth of cosmic string investigations. The outcomes of such studies hold promising implications for the validation of higher-dimensional universe theories and the interpretation of early universe dynamics.