Red Magnitude Research Articles

Photometric analysis of Type Ia Supernova 2023jvj

The study of supernovae – large explosions at the end of a star’s life that release immense energy and various elements into space – is important in the fields of stellar evolution and the expansion of the universe. In the large cosmological time scale, supernovae allow for a short glimpse into the universe’s evolution. Upon the discovery of Supernova (SN) 2023jvj, located in an anonymous galaxy in the Boötes constellation, our team launched an investigation to further knowledge of transient objects and their role in the cosmos. In this study, we conducted a photometric analysis of SN 2023jvj to determine its type and distance. We hypothesized SN 2023jvj would be a Type Ia supernova based on reports that there were no hydrogen spectral lines. We observed SN 2023jvj and collected photometric data over four weeks using the 12-inch Meade Schmidt Cassegrain Telescope (SCT) and 16-inch Ritchey-Chretien Telescope (RCT) at the Leitner Family Observatory and Planetarium (LFOP). Images were additionally collected remotely from Australia and Utah via the iTelescope Network. Using this data, standard Sloan green and Sloan red magnitudes were found through color calibration and used to generate a light curve (a plot of supernova brightness over time). SN 2023jvj was then determined to be a Type Ia supernova — a standard candle — with a distance modulus of 35.36. Therefore, SN 2023jvj is approximately 1.246e8 parsecs away from Earth. Our findings have a broader impact on how astronomers analyze the relationship between the brightness and distance of transient objects in the ever-expanding universe.

New Observations of Galaxies with Ultraviolet Excess

Results from a spectral study of galaxies with UV excess from the Kazarian list obtained with the 2.6-m telescope at the Byurakan Astrophysical Observatory in Armenia are presented. Measurements of red shifts, distances, absolute magnitudes, and magnitudes in the B, V, R, and I bands are reported.

Characterizing the optical properties of galaxy clusters with GMPhoRCC

We introduce the Gaussian Mixture full Photometric Red sequence Cluster Characteriser (GMPhoRCC), an algorithm for determining the redshift and richness of a galaxy cluster candidate. By using data from a multi-band sky survey with photometric redshifts, a red sequence colour magnitude relation (CMR) is isolated and modelled and used to characterise the optical properties of the candidate. GMPhoRCC provides significant advantages over existing methods including, treatment of multi-modal distributions, variable width full CMR red sequence, richness extrapolation and quality control in order to algorithmically identify catastrophic failures. We present redshift comparisons for clusters from the GMBCG, NORAS, REFLEX and XCS catalogues, where the GMPhoRCC estimates are in excellent agreement with spectra, showing accurate, unbiased results with low scatter ($\sigma_{\delta z / (1+z)} \sim 0.014$). We conclude with the evaluation of GMPhoRCC performance using empirical Sloan Digital Sky Survey (SDSS) like mock galaxy clusters. GMPhoRCC is shown to produce highly pure characterisations with very low probabilities ($<1\%$) of spurious, clean characterisations. In addition GMPhoRCC is shown to demonstrate high rates of completeness with respect to recovering redshift, richness and correctly identifying the BCG.

An All-Sky Portable (ASP) Optical Catalogue

AbstractThis optical catalogue combines the all-sky USNO-B1.0/A1.0 and most-sky APM catalogues, plus overlays of SDSS optical data, into a single all-sky map presented in a sparse binary format that is easily downloaded at 9 Gb zipped. Total count is 1 163 237 190 sources and each has J2000 astrometry, red and blue magnitudes with PSFs and variability indicator, and flags for proper motion, epoch, and source survey and catalogue for each of the photometry and astrometry. The catalogue is available on http://quasars.org/asp.html, and additional data for this paper is available at http://dx.doi.org/10.4225/50/5807fbc12595f.

DISAPPEARANCE OF COMET C/2010 X1 (ELENIN): GONE WITH A WHIMPER, NOT A BANG

We examine the rise and sudden demise of comet C/2010 X1 (Elenin) on its approach to perihelion. Discovered inbound at 4.2 AU, this long-period comet was predicted to become very bright when near perihelion, at 0.48 AU on 2011 September 10. Observations starting 2011 February (heliocentric distance $\sim$3.5 AU) indeed show the comet to brighten by about 11 magnitudes, with most of the increase occurring inside 1 AU from the Sun. The peak brightness reached $m_R$ = 6 on UT 2011 August 12.95$\pm$0.50, when at $\sim$0.83 AU from the Sun. We find that most of the surge in brightness in mid-August resulted from dust particle forward-scattering, not from a sudden increase in the activity. A much smaller ($\sim$3 magnitudes) brightening reached a maximum on UT 2011 August 30$\pm$1 (at 0.56 AU), and reflects the true break-up of the nucleus. This second peak was matched by a change in the morphology from centrally condensed to diffuse. The estimated cross-section of the nucleus when at 1 AU inbound was $\sim$1 km$^2$, corresponding to an equal-area circle of radius 0.6 km. No surviving fragments were found to a limiting red magnitude $r'$ = 24.4, corresponding to radii $\lesssim$40 m (red geometric albedo = 0.04 assumed). Our observations are consistent with disintegration of the nucleus into a power law size distribution of fragments with index $q$ = 3.3$\pm$0.2 combined with the action of radiation pressure. We speculate about physical processes that might cause nucleus disruption in a comet when still 0.7 AU from the Sun. Tidal stresses and devolatilization of the nucleus by sublimation are both negligible at this distance. However, the torque caused by mass loss, even at the very low rates measured in comet Elenin, is potentially large enough to be responsible by driving the nucleus to rotational instability.

A cosmological distance scale program

A program for identifying the cosmological distance scale for different models of the red shift in the spectra of extragalactic sources from the observed red shifts and stellar magnitudes, combined with the database on supernovae, radio galaxies and quasars, is developed. The Friedmann–Mattig and generalized interpolation models in combination with models of the intrinsic red shift of the sources are taken as the main parameters.

Cosmological distance scale based on a red-shift interpolation model

A unified scale of cosmological distances from 0.01 to 13.18 billion light years is constructed from the observed red shifts and stellar magnitudes of 440 quasars, radio galaxies, and galaxies in the Local volume based on an interpolation model with a discontinuity of the second kind and Arp–Trumpler correction to the intrinsic red shift.

Unifying the planar bar and the boxy bulge of the Milky Way

For some time the Milky Way has been understood as a barred disk galaxy. Star count observations have provided evidence for two bars at apparently different orientations, the boxy bulge and a long planar bar. We report recent work in which we argued for a scenario where these observations can be reproduced with a single boxy bulge/bar: an evolved bar from the stellar disk and the corresponding boxy bulge generated from it through secular evolution and buckling instability. We calculated the star count distributions along different lines-of-sight for a simulated barred galaxy and an observer at the Sun position, and compared them with observations of red clump magnitude distributions. We found a good agreement between the model and the observations, even though the simulation has a single boxy bulge/bar. In this model, the different apparent orientations of the boxy bulge and planar bar are partially due to the volume effect and partially to the leading ends of the bar.

A catalog of Kazarian galaxies

The entire Kazarian galaxies (KG) catalog is presented, which combines extensive new measurements of their optical parameters with a literature and database search. The measurements were made using images extracted from the STScI Digitized Sky Survey (DSS) of Jpg(blue), Fpg(red), and Ipg(NIR) band photographic sky survey plates obtained by the Palomar and UK Schmidt telescopes. We provide accurate coordinates, morphological types, spectral and activity classes, blue apparent diameters, axial ratios, position angles, red, blue, and NIR apparent magnitudes, as well as counts of neighboring objects in a circle of radius 50 kpc from centers of KG. Special attention was paid to the individual descriptions of the galaxies in the original Kazarian lists, which clarified many cases of misidentifications of the objects, particularly among interacting systems. The total number of individual Kazarian objects in the database is now 706. We also include the redshifts, which are now available for 404 galaxies and the 2MASS infrared magnitudes for 598 KG. The database also includes extensive notes, which summarize information about the membership of Kazarian galaxies in different systems of galaxies and about revised activity classes and redshifts. An atlas of several interesting subclasses of Kazarian galaxies is also presented.

A survey for satellites of Venus

We present a systematic survey for satellites of Venus using the Baade–Magellan 6.5 m telescope and IMACS wide-field CCD imager at Las Campanas observatory in Chile. In the outer portions of the Hill sphere the search was sensitive to a limiting red magnitude of about 20.4, which corresponds to satellites with radii of a few hundred meters when assuming an albedo of 0.1. In the very inner portions of the Hill sphere scattered light from Venus limited the detection to satellites of about a kilometer or larger. Although several main belt asteroids were found, no satellites (moons) of Venus were detected.

New High Proper Motion Stars from the Digitized Sky Survey. III. Stars with Proper Motions 0."45 &lt; μ &lt; 2."0 yr-1South of Declination -30°

We report the discovery of 182 southern stars with proper motion larger than 045 yr-1. The stars were found in an expansion of the SUPERBLINK proper-motion survey to 8980 deg2 south of decl. = -30?. The new high proper motion stars include 123 objects with ? > 05 yr-1 and 5 with ? > 10 yr-1. These newfound stars consist of a variety of nearby red dwarfs and white dwarfs and (slightly more distant) red halo subdwarfs, and they are all prime targets for follow-up spectroscopic and astrometric (parallax) observations. Comparison with previous proper-motion surveys in the southern sky suggests that SUPERBLINK has a recovery rate between 80% and 90% at southern declinations for stars with red magnitude 10 mag < RF < 19 mag and proper motion in the range 05 < ? < 20 yr-1. This survey makes a significant addition to the census of high proper motion stars at southern declinations.

An Ultradeep Survey for Irregular Satellites of Uranus: Limits to Completeness

We present a deep optical survey of Uranus's Hill sphere for small satellites. The 8 m Subaru Telescope was used to survey about 3.5 square degrees with a 50% detection efficiency at limiting red magnitude mR = 26.1. This magnitude corresponds to objects that are about 7 km in radius (assuming an albedo of 0.04). We detected (without prior knowledge of their positions) all previously known outer satellites and discovered two new irregular satellites (S/2001 U2 and S/2003 U3). The two inner satellites Titania and Oberon were also detected. One of the newly discovered bodies (S/2003 U3) is the first known irregular prograde satellite of the planet. The population, size distribution, and orbital parameters of Uranus's irregular satellites are remarkably similar to those of the irregular satellites of gas giant Jupiter. Both have shallow size distributions (power-law indices q ~ 2 for radii larger than 7 km) with no correlation between the sizes of the satellites and their orbital parameters. However, unlike those of Jupiter, Uranus's irregular satellites do not appear to occupy tight, distinct dynamical groups in semimajor-axis versus inclination phase space. Two groupings in semimajor-axis versus eccentricity phase space appear to be statistically significant.

A Survey for Outer Satellites of Mars: Limits to Completeness

We have surveyed the Hill sphere of Mars for irregular satellites. Our search covered nearly the entire Hill sphere, but scattered light from Mars excluded the inner few arcminutes where the satellites Phobos and Deimos reside. No new satellites were found to an apparent limiting red magnitude of 23.5, which corresponds to radii of about 0.09 km using an albedo of 0.07.

The Size Distribution of Kuiper Belt Objects

We describe analytical and numerical collisional evolution calculations for the size distribution of icy bodies in the Kuiper belt. For a wide range of bulk properties, initial masses, and orbital parameters, our results yield power-law cumulative size distributions, NC ∝ r-q, with qL ≈ 3.5 for large bodies (with radii r ≳ 10–100 km) and qS ≈ 2.5–3 for small bodies (with radii r ≲ 0.1–1 km). The transition between the two power laws occurs at a break radius rb ≈ 1–30 km. The break radius is more sensitive to the initial mass in the Kuiper belt and the amount of stirring by Neptune than to the bulk properties of individual Kuiper belt objects (KBOs). Comparisons with observations indicate that most models can explain the observed sky surface density σ(m) of KBOs for red magnitudes R ≈ 22–27. For R ≲ 22 and R ≳ 28, the model σ(m) is sensitive to the amount of stirring by Neptune, suggesting that the size distribution of icy planets in the outer solar system provides independent constraints on the formation of Neptune.

Discovery of five irregular moons of Neptune.

Each giant planet of the Solar System has two main types of moons. 'Regular' moons are typically larger satellites with prograde, nearly circular orbits in the equatorial plane of their host planets at distances of several to tens of planetary radii. The 'irregular' satellites (which are typically smaller) have larger orbits with significant eccentricities and inclinations. Despite these common features, Neptune's irregular satellite system, hitherto thought to consist of Triton and Nereid, has appeared unusual. Triton is as large as Pluto and is postulated to have been captured from heliocentric orbit; it traces a circular but retrograde orbit at 14 planetary radii from Neptune. Nereid, which exhibits one of the largest satellite eccentricities, is believed to have been scattered from a regular satellite orbit to its present orbit during Triton's capture. Here we report the discovery of five irregular moons of Neptune, two with prograde and three with retrograde orbits. These exceedingly faint (apparent red magnitude m(R) = 24.2-25.4) moons, with diameters of 30 to 50 km, were presumably captured by Neptune.

Long-Term Photometric Behavior of 18 Carbon Stars in Cygnus

Abstract The large variety of long-term (secondary) variations is demonstrated on the basis of a 30 year long photographic red magnitude time-series for 18 carbon stars in Cygnus based on the observations carried out with the Baldone Schmidt telescope.

143P/Kowal-Mrkos and the Shapes of Cometary Nuclei

We add 143P/Kowal-Mrkos to the small but growing sample of well-observed cometary nuclei. Photometric observations from 3.4 to 4.0 AU heliocentric distance reveal a pointlike object with no detectable outgassing. Periodic modulation of the scattered light (ΔmR = 0.45 ± 0.05) is attributed to rotation of the bare nucleus with a double-peaked period 17.21 ± 0.10 hr and a projected ratio of the shortest to longest axis of about 0.67/1. We also measured the phase coefficient (0.043 ± 0.014 mag deg-1), the BVRI colors (V-R = 0.58 ± 0.02), and the absolute red magnitude [mR(1, 1, 0) = 13.49 ± 0.20]. The effective circular radius is 5.7 ± 0.6 km (geometric albedo 0.04 assumed). We study the properties of 11 well-observed Jupiter-family comet (JFC) nuclei. On average, the nuclei are systematically more elongated (average photometric range = 0.54 ± 0.07) than main-belt asteroids of comparable size ( = 0.32 ± 0.05) and more elongated than fragments produced in laboratory impact experiments. We attribute the elongation of the nuclei to an evolutionary effect, most likely driven by sublimation-induced mass loss. However, we find no evidence for any relation between the nucleus shape and the sublimation timescale. This may be because the timescale for evolution of the nucleus shape is very short compared with the dynamical timescale for the JFCs, meaning that most nuclei in our sample are already highly physically evolved.

The Caltech Wide Area Sky Survey

The first phase of the Caltech Wide Area Sky Survey occurred from late November 2001 through mid-April 2003. We present preliminary results from this survey which has detected 28 bright Kuiper Belt Objects (KBOs) and 4 Centaurs, 19 of which were discovered in our survey including Quaoar, the largest KBO, as well as 6 of the 10 intrinsically brightest KBOs. We have surveyed 5108 square degrees of the sky nearest the invariable plane to a limiting red magnitude of 20.7. Correcting for the overabundance of objects near the invariable plane, this represents 27% completeness in terms of KBO numbers. Thus, approximately 100 KBOs and Centaurs brighter than m_R = 20.7 exist, about 3/4 of which remain undiscovered. The bright KBOs are consistent with the canonical q = 4 size distribution, suggesting that about ten 1000 km diameter KBOs and about one 2000 km diameter KBO exist. Additionally, we observe only 3 KBOs with low inclination (i < 7 degrees) with 67% of the sky available to these objects surveyed. This is in sharp contrast with the known KBOs, of which about 60% of the ∼ 800 observed objects (as of May 2003) have i < 7 degrees. Although we observe at systematically higher invariable plane latitudes than many deeper KBO surveys, such systematic biases cannot fully explain the lack of low inclination objects, a measurement which is significant at the > 3σ level. This suggests that the bright KBOs have a fundamentally different maximum size than the fainter KBOs. A better characterization of the survey limiting magnitude and a more thorough modeling of observational bias effects of different classes of KBOs will be made in a future work.

Study of variable stars in the MOA data base: long-period red variables in the Large Magellanic Cloud

One hundred and forty six long-period red variable stars in the Large Magellanic Cloud (LMC) from the three year MOA project database were analysed. A careful periodic analysis was performed on these stars and a catalogue of their magnitudes, colours, periods and amplitudes is presented. We convert our blue and red magnitudes to $K$ band values using 19 oxygen-rich stars. A group of red short-period stars separated from the Mira sequence has been found on a (log P, K) diagram. They are located at the short period side of the Mira sequence consistent with the work of Wood and Sebo (1996). There are two interpretations for such stars; a difference in pulsation mode or a difference in chemical composition. We investigated the properties of these stars together with their colour, amplitude and periodicity. We conclude that they have small amplitudes and less regular variability. They are likely to be higher mode pulsators. A large scatter has been also found on the long period side of the (log P, K) diagram. This is possibly a systematic spread given that the blue band of our photometric system covers both standard B and V bands and affects carbon-rich stars.

Large Bodies in the Kuiper Belt

We present a survey for bright Kuiper Belt objects (KBOs) and Centaurs, conducted at the Kitt Peak National Observatory (KPNO) 0.9 m telescope with the KPNO 8K Mosaic CCD. The survey imaged 164 deg2 near opposition to a limiting red magnitude of 21.1. Three bright KBOs and one Centaur were found, the brightest KBO having red magnitude 19.7, about 700 km in diameter, assuming a dark Centaur-like 4% albedo. We estimate the power-law differential size distribution of the classical KBOs to have index q = 4.2, with the total number of classical KBOs with diameters larger than 100 km equal to 4.7 × 104. Additionally, we find that if there is a maximum object size in the Kuiper Belt, it must be larger than 1000 km in diameter. By extending our model to larger size bodies, we estimate that 30 Charon-sized and 3.2 Pluto-sized classical KBOs remain undiscovered.