A significant discovery has been made in the field of astronomy, with 19 new quasars, including strongly-lensed, dual, and projected types, identified through analysis of data from the DESI Legacy Surveys photometry catalog. This breakthrough highlights the potential of quasar observations in furthering our understanding of the universe. These objects, known for their extreme luminosity and powered by supermassive black holes, have long been pivotal for research into astrophysics and cosmology. Observations were conducted at the Palomar Observatory in California.

Findings of the DESI Legacy Surveys

According to the study led by Zizhao He of the Purple Mountain Observatory, the investigation confirmed two strongly-lensed quasars, six dual quasars, and 11 projected quasars. Observations were carried out on October 15–16, 2023, using the P200/DBSP instrument. The study noted that the lensed quasars, designated J0746+1344 and J2121-0826, were observed at redshifts of 3.1 and 2.39, respectively. J0746+1344 displayed a unique configuration, with the lensing galaxy positioned beside the brightest image—an anomaly compared to typical observations.

Dual and Projected Quasars

As reported by phys.org, the six dual quasars identified showed redshifts ranging from 0.59 to 3.28, with separations between their components varying from 50,300 to 73,500 light years. Among these, J1929+6009 stood out due to a remarkably small redshift difference of less than 0.0001 and a projected separation of 62,800 light years.

The 11 projected quasars demonstrated separations spanning 35,700 to 123,400 light years. One such system, J0422+0047, was previously thought to be a gravitationally-lensed quasar system, though further analysis indicated a chance alignment of projected quasars with an intervening galaxy, complicating its classification.

Implications of the Discovery

This research underscores the importance of advanced observational techniques in uncovering unique cosmic phenomena. By analysing the behaviour, redshifts, and configurations of these quasars, astronomers aim to expand their knowledge of the universe’s structure and the dynamics of supermassive black holes.

A major scientific breakthrough is anticipated with the Vera C. Rubin Observatory, currently under construction on Cerro Pachón in Chile, as it prepares to embark on its decade-long Legacy Survey of Space and Time (LSST). Scheduled to commence this year, this endeavour is expected to detect millions of Type Ia supernovae, commonly referred to as “vampire stars” due to their ability to siphon material from nearby stellar companions. The data collected is likely to offer unprecedented insights into dark energy, the enigmatic force responsible for the universe’s accelerating expansion.

Significance of Type Ia Supernovae in Measuring Cosmic Distances

According to a report by space.com, Type Ia supernovae, resulting from the explosive end of white dwarf stars, have proven invaluable in cosmic measurements. Their light output is consistent, making them effective “standard candles” for determining distances across the universe. By analysing the brightness and colour of these supernovae, combined with data from their host galaxies, astronomers can map the extent of the universe’s expansion over time. Anais Möller, a researcher with the Rubin/LSST Dark Energy Science Collaboration, noted that the observatory would generate a diverse sample of Type Ia supernovae from different distances and galaxy types, enabling a broader understanding of their behaviour.

Mechanisms Behind Type Ia Supernovae

As per scientific findings, white dwarf stars form when sun-like stars exhaust their nuclear fuel, leaving behind dense, collapsed cores. These stellar remnants can reach critical mass by accumulating material from a companion star in binary systems. Upon surpassing the Chandrasekhar limit of approximately 1.4 solar masses, the white dwarfs erupt in Type Ia supernovae, often obliterating themselves entirely. Such explosions, while abundant, occur unpredictably, presenting a challenge for long-term observation.

Advancing Dark Energy Research

The observatory is expected to revolutionise dark energy studies by producing extensive data, allowing researchers to refine models of cosmic expansion. Since dark energy’s discovery in 1998, its exact nature has remained elusive, with theories suggesting it constitutes around 68% of the universe’s energy and matter. By observing the universe’s expansion at different cosmic epochs, Rubin’s data is anticipated to clarify whether dark energy’s influence has remained constant or evolved over time.

Preparing for a Data Avalanche

With nightly scans of the southern hemisphere, the observatory is projected to generate up to 20 terabytes of data daily, issuing millions of alerts to astronomers worldwide. Software systems are being developed to handle this data influx, identifying transient events like supernovae and kilonovas. Researchers, including Anais Möller, have emphasised the project’s transformative potential, calling it a generational leap in astronomical science.