Vera C. Rubin Observatory

Abstract As the frontier of precision astronomical photometry continues to advance, correcting for time-variable atmospheric transmission becomes increasingly important. We describe an observational approach to monitoring optical attenuation due to atmospheric aerosols, using a multiband filter and disperser on the Auxiliary Telescope at the Vera C. Rubin Observatory. This configuration allows us to perform simple aperture photometry on four notched-out spectral regions, covering 347–618 nm. We see clear evidence of temporal variations in extinction across these bands, which we attribute to variation in the aerosol content of the atmosphere above the observatory. The observed differences in extinction between the reddest and bluest band can exceed 5 mmag/airmass, highlighting the importance of including variable aerosols in the transmission of the atmosphere. We aspire to using precise determinations of the optical transmission of the atmosphere to enable a forward-modeling approach to achieving mmag photometric precision with Rubin data.

Previous wide-field surveys have observed a sharp decline in the radial distribution of Kuiper Belt Objects (KBOs) around 50 au, known as the Kuiper Cliff. Recently, the New Horizons Subaru TNO (Trans-Neptunian object) Survey found an increase in the radial distribution of KBOs at 70 au (using the shift-and-stack method with a r-band limiting magnitude of 26.5). From these results, Fraser et al. (2024) posit that the existence of a previously unknown secondary belt/population of distant small bodies beyond the Kuiper belt can explain the uptick in detections beyond 70 au. To further test and constrain this population model, we used data from the Dark Energy Survey (DES). The DES, with a limiting magnitude of 23.8 in r-band, discovered 812 KBOs (Bernardinelli et al., 2022), but none are consistent with a second distant belt of objects. Using the constraints from DES and the New Horizons Subaru TNO Survey, we will examine implications for the Vera C. Rubin Observatory to discover this distant belt if it exists. Starting later this year, the Rubin Observatory will begin science operations and start taking images of the sky as part of the Legacy Survey of Space and Time. The LSST’s capability to detect this distant small body population will be unprecedented, given its significantly increased sky coverage (~20,000 square degrees) and depth (24.5 in r-mag). Alongside predictions for its single exposures, we created predictions for LSST’s discovery rate when using the shift-and-stack techniques in the deep drilling fields, which is expected to push the detection limit to 27 mag.

The Vera C. Rubin Observatory is a new NSF/DOE-funded facility on Cerro Pachón, Chile. It houses the 8.4m Simonyi Survey Telescope and the 3.2 Gigapixel LSSTCam camera. The Observatory is in the final stages of commissioning, expected to enter operations by the end of 2025. Once operational, Rubin will execute the Legacy Survey of Space and Time (LSST). Enabled by its 9.6 square degree field of view and a cadence covering the sky every 3-4 days to ~24.5 mag, the LSST dataset will dramatically advance numerous area of astronomy, including our understanding of the Solar System by delivering the largest catalog of small bodies to date.This talk will present the first public Solar System-related results from Rubin's early commissioning efforts. We will discuss the discovery yields, measured performance of the observatory, early comparison to predictions, and talk through the expectations for further data during commissioning's Science Validation surveys. With a steady stream of public solar system discoveries expected to start in late commissioning, small bodies are likely to be one of the first areas of highly impactful early science. We hope this talk will help prepare the Solar System community for those imminent opportunities, and illustrate the transformational capabilities that Rubin is about to bring.

Due to their short timescale, stellar flares are a challenging target for the most modern synoptic sky surveys. The upcoming Vera C. Rubin Legacy Survey of Space and Time (LSST), a project designed to collect more data than any precursor survey, is unlikely to detect flares with more than one data point in its main survey. We developed a methodology to enable LSST studies of stellar flares, with a focus on flare temperature and temperature evolution, which remain poorly constrained compared to flare morphology. By leveraging the sensitivity expected from the Rubin system, differential chromatic refraction (DCR) can be used to constrain flare temperature from a single-epoch detection, which will enable statistical studies of flare temperatures and constrain models of the physical processes behind flare emission using the unprecedentedly high volume of data produced by Rubin over the 10 yr LSST. We model the refraction effect as a function of the atmospheric column density, photometric filter, and temperature of the flare, and show that flare temperatures at or above ∼4000 K can be constrained by a single g-band observation at air mass X ≳ 1.2, given the minimum specified requirement on the single-visit relative astrometric accuracy of LSST, and that a surprisingly large number of LSST observations are in fact likely be conducted at X ≳ 1.2, in spite of image quality requirements pushing the survey to preferentially low X. Having failed to measure flare DCR in LSST precursor surveys, we make recommendations on survey design and data products that enable these studies in LSST and other future surveys.

Luka pasca operasi dapat berisiko mengalami infeksi apabila perawatan luka yang dilakukan kurang tepat. Tujuan penulisan ini untuk mengetahui hasil asuhan keperawatan perioperatif dengan penggunaan transparan film dressing dalam pencegahan resiko infeksi luka post operasi Sectio Caesarea (SC) di Ruang Mawar RSUD dr. Rubini Mempawah. Karya ilmiah ini berbentuk deskriptif dengan studi kasus melalui proses keperawatan yang terdiri dari pengkajian, analisa data, penegakan Diagnosis, implementasi perawatan luka dengan inovasi Transparent Film Dressing pada pasien post SC di ruang mawar RSUD dr. Rubini Mempawah dan evaluasi dilihat proses penyembuhan luka di hari pertama hingga hari ke tiga pasien dirawat. Berdasarkan hasil pengelolaan kasus selama tiga hari tidak ditemukan adanya tanda-tanda infeksi pada luka pasca operasi. Luka tampak bersih dan kering. Hasil penilaian Southampton Wound Assessment Scale adalah 0 yang artinya penyembuhan normal. Kesimpulan, transparent film dressing dapat membantu mempercepat proses penyembuhan luka pasca operasi karena meminimalkan kontak luka dengan lingkungan luar setiap hari yang dapat menyebabkan risiko infeksi. Transparent film dressing dapat menjadi pilihan yang efektif dan efisien biaya karena balutan lebih tahan lama dan lebih mudah dimonitoring karena bersifat transparan.

The Gemini High Resolution Optical Spectrograph (GHOST) is a fiber-fed spectrograph system on the Gemini South telescope that provides simultaneous wavelength coverage from 348 to 1061 nm, and is designed for optimal performance between 363 and 950 nm. It can observe up to two objects simultaneously in a 7.′5 diameter field of regard at R ≃ 56,000 or a single object at R ≃ 75,000. The spectral resolution modes are obtained by using integral field units to image slice a 1.″2 aperture by a factor of five in width using 19 fibers in the high resolution mode and by a factor of three in width using 7 fibers in the standard resolution mode. GHOST is equipped with hardware to allow for precision radial velocity measurements, expected to approach meters per second precision. Here, we describe the basic design and operational capabilities of GHOST, and proceed to derive and quantify the key aspects of its on-sky performance that are of most relevance to its science users.

In order to improve our understanding of the satellite populations of low-mass galaxies, the DECam Local Volume Exploration (DELVE) – DEEP Survey is performing a search for satellites around the isolated, low-mass galaxy, NGC 55. As part of this search, we characterize our dwarf galaxy detection sensitivity by injecting artificial dwarf galaxies into our data set and measuring the fraction that we can recover. Additionally, we inject and recover artificial dwarfs to test how the blending of resolved stars affects the detection of dwarf galaxies. We inject 650 artificial dwarfs across 26 DELVE-DEEP coadded images of the NGC 55 halo and use the software tool, Source Extractor, to perform source recovery. A dwarf-search pipeline is then run on our dwarf-injected catalogs, utilizing the photutils function, find peaks, and detections are recorded as a function of dwarf size and luminosity. Our results demonstrate that we are most sensitive to large, bright dwarf galaxies, and our sensitivity begins to decrease as we approach DELVE-DEEP’s detection limit or blending causes significant reductions in recovered magnitude. We also find that our results are hindered by the limitations of star-galaxy separation applied to distant, faint sources, which is possibly a consequence of the blending of small star clusters within dwarf galaxies.

The Vera C. Rubin Legacy Survey of Space and Time (LSST) holds the potential to revolutionize time domain astrophysics, reaching completely unexplored areas of the Universe and mapping variability time scales from minutes to a decade. To prepare to maximize the potential of the Rubin LSST data for the exploration of the transient and variable Universe, one of the four pillars of Rubin LSST science, the Transient and Variable Stars Science Collaboration, one of the eight Rubin LSST Science Collaborations, has identified research areas of interest and requirements, and paths to enable them. While our roadmap is ever-evolving, this document represents a snapshot of our plans and preparatory work in the final years and months leading up to the survey’s first light.

This report is the result of a joint discussion between the Rubin and Euclid scientific communities. The work presented in this report was focused on designing and recommending an initial set of Derived Data products (DDPs) that could realize the science goals enabled by joint processing. All interested Rubin and Euclid data rights holders were invited to contribute via an online discussion forum and a series of virtual meetings. Strong interest in enhancing science with joint DDPs emerged from across a wide range of astrophysical domains: Solar System, the Galaxy, the Local Volume, from the nearby to the primaeval Universe, and cosmology.

The Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST) will perform precision photometry of resolved and unresolved objects over the visible sky at a 3-day cadence using an 8.4-meter diameter telescope that forms an image of the sky on a 3.2 Gigapixel focal plane array. Meeting and exceeding the photometric precision requirements is a significant challenge and necessitates the calibration and correction of multiple forms of systematic error. This paper describes multiple novel hardware systems that Rubin is developing to measure and compensate for numerous sources of systematic errors, particularly errors impacting photometry measurements.