Physical properties of near-Earth asteroids manually recovered from NEOWISE data

The Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) spacecraft was reactivated in December 2013 and since then has been conducting an all-sky survey at 3.4 and 4.6 microns to discover and characterize asteroids and comets that come close to the Earth.&#160; NEOWISE employs an automated pipeline for the detection of moving objects, recording their astrometry and photometry and reporting positions to the Minor Planet Center for archiving.&#160; However, there are a subset of near-Earth objects that are not found by the automated system due to rates of motion or acceleration outside the pipeline limits, an insufficient number of detections, or confusion with background sources.&#160; Because NEOWISE archives every full-frame image obtained during the survey, detections of these objects can be recovered by manually searching the expected positions for coincident sources. We have performed searches for near-Earth objects in the NEOWISE archives from 2013 to 2019, recovering detections for over 400 objects and enabling fitting of their diameters and albedos (Masiero et al. 2018, Masiero et al. 2020).&#160; This builds on earlier work that searched the data from the cryogenic phase of the original WISE mission (Mainzer et al. 2014).&#160; Objects found through this technique tend to be smaller than those detected by the automated processing. The distribution of albedos for these objects is skewed to high reflectivities, as is expected for a population that is optically-selected. Here we present the results of our searches along with the physical properties of the recovered objects.&#160; We also will discuss the reasons these objects were missed by the automated processing, and what the observed physical property distribution implies about any remaining objects still waiting to be found in the data.

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New Tools for the Optimized Follow-Up of Imminent Impactors

Universe ◽

10.3390/universe7010010 ◽

2021 ◽

Vol 7 (1) ◽

pp. 10

Author(s):

Maddalena Mochi ◽

Giacomo Tommei

Keyword(s):

Orbit Determination ◽

Main Belt ◽

Impact Monitoring ◽

The Earth ◽

Current Observation ◽

Short Period ◽

Fly Eye ◽

Near Earth Asteroids ◽

Near Earth Objects

The solar system is populated with, other than planets, a wide variety of minor bodies, the majority of which are represented by asteroids. Most of their orbits are comprised of those between Mars and Jupiter, thus forming a population named Main Belt. However, some asteroids can run on trajectories that come close to, or even intersect, the orbit of the Earth. These objects are known as Near Earth Asteroids (NEAs) or Near Earth Objects (NEOs) and may entail a risk of collision with our planet. Predicting the occurrence of such collisions as early as possible is the task of Impact Monitoring (IM). Dedicated algorithms are in charge of orbit determination and risk assessment for any detected NEO, but their efficiency is limited in cases in which the object has been observed for a short period of time, as is the case with newly discovered asteroids and, more worryingly, imminent impactors: objects due to hit the Earth, detected only a few days or hours in advance of impacts. This timespan might be too short to take any effective safety countermeasure. For this reason, a necessary improvement of current observation capabilities is underway through the construction of dedicated telescopes, e.g., the NEO Survey Telescope (NEOSTEL), also known as “Fly-Eye”. Thanks to these developments, the number of discovered NEOs and, consequently, imminent impactors detected per year, is expected to increase, thus requiring an improvement of the methods and algorithms used to handle such cases. In this paper we present two new tools, based on the Admissible Region (AR) concept, dedicated to the observers, aiming to facilitate the planning of follow-up observations of NEOs by rapidly assessing the possibility of them being imminent impactors and the remaining visibility time from any given station.

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H i galaxies with little star formation: an abundance of LIERs

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz593 ◽

2019 ◽

Vol 485 (3) ◽

pp. 3169-3184 ◽

Cited By ~ 6

Author(s):

Vaishali Parkash ◽

Michael J I Brown ◽

T H Jarrett ◽

A Fraser-McKelvie ◽

M E Cluver

Keyword(s):

Star Formation ◽

Emission Line ◽

Central Star ◽

Wide Field ◽

Dark Energy Survey ◽

Sky Survey ◽

Low Levels ◽

Field Unit ◽

Energy Survey ◽

Infrared Survey

Abstract We present a sample of 91 H i galaxies with little or no star formation, and discuss the analysis of the integral field unit (IFU) spectra of 28 of these galaxies. We identified H i galaxies from the H i Parkes All-Sky Survey Catalog (HICAT) with Wide-field Infrared Survey Explorer (WISE) colours consistent with low specific star formation (<10−10.4 yr−1), and obtained optical IFU spectra with the Wide-Field Spectrograph (WiFeS). Visual inspection of the PanSTARRS, Dark Energy Survey, and Carnegie-Irvine imaging of 62 galaxies reveals that at least 32 galaxies in the sample have low levels of star formation, primarily in arms/rings. New IFU spectra of 28 of these galaxies reveals 3 galaxies with central star formation, 1 galaxy with low-ionization nuclear emission-line regions (LINERs), 20 with extended low-ionization emission-line regions (LIERs), and 4 with high excitation Seyfert (Sy) emission. From the spectroscopic analysis of H i selected galaxies with little star formation, we conclude that 75 per cent of this population are LINERs/LIERs.

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Evidence of AGN-driven Outflows in Young Radio Quasars Selected from the Wide-field Infrared Survey Explorer

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314004268 ◽

2013 ◽

Vol 9 (S304) ◽

pp. 347-348

Author(s):

Minjin Kim ◽

Luis C. Ho ◽

Carol J. Lonsdale ◽

Mark Lacy ◽

Andrew W. Blain ◽

...

Keyword(s):

Active Galactic Nuclei ◽

Near Infrared ◽

Galactic Nuclei ◽

Emission Lines ◽

Wide Field ◽

Near Infrared Spectra ◽

Sky Survey ◽

Line Widths ◽

Infrared Survey ◽

Narrow Emission

AbstractWe present near-infrared spectra of young radio quasars selected by cross-correlating the Wide-field Infrared Survey Explorer (WISE) all-sky survey catalog with the radio catalog [Faint Images of the Radio Sky at Twenty cm (FIRST) and NRAO VLA Sky Survey (NVSS)]. The objects have typical redshifts of z ≈ 2 and [O III] luminosities of 107 erg s−1 comparable to those of luminous quasars. The observed flux ratios of narrow emission lines indicate that these objects appear to be powered by active galactic nuclei. The [O III] line is broad, with full width at half maximum ~1300 to 2100 km s−1, significantly larger than that of ordinary quasars. These large line widths might be explained by jet-induced outflows.

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Synergy of wide-field infrared survey explorer (WISE) and the Sloan Digital Sky Survey in Stripe 82

10.32469/10355/66177 ◽

2018 ◽

Author(s):

◽

Marat Musin

Keyword(s):

Stellar Mass ◽

Sloan Digital Sky Survey ◽

High Mass ◽

Optical Data ◽

Wide Field ◽

Resolution Image ◽

Sky Survey ◽

Template Fitting ◽

Very High ◽

Infrared Survey

In this dissertation, I aim to study the evolution of galaxies over the last 6 Gyr by measuring the growth of the global stellar mass density (GSMD) since z = 0.8. My work combines the datasets from two very large surveys, namely, the optical data from the Sloan Digital Sky Survey (SDSS) Stripe 82 and the infrared data from the Wide-field Infrared Survey Explorer (WISE), and constructs a unique catalog of galaxies that have their spectral energy distributions (SEDs) measured consistently from 0.3 to 5 [mu]m in seven bands. This catalog, the largest of its kind, contains 9 million galaxies in [about] 300 deg[2] , will have a wide range of applications beyond the scope of this thesis. Extending galaxy SED measurements to restframe near-IR has two significant advantages: (1) dust extinction can be better handled, and (2) emissions from low-mass stars, which are the major contributors to a galaxy's stellar mass, can be better measured. WISE was the only mission to date that provided all-sky IR data that are deep enough for galaxy evolution studies out to z [approximately] 1 (sampling restframe K-band). The only wide-field optical survey data that could match WISE depths are those from the SDSS Stripe 82 over [about] 300 deg2 . The synergy of the two is therefore natural. The implementation, however, is of tremendous difficulty. This is mainly because of the vastly different spatial resolutions between SDSS and WISE. To overcome this problem, we take an approach that is often referred to as "morphological template fitting", i.e., using the high-resolution image to define the morphological template of the galaxy in question, and de-convolving its light profile in the low-resolution image accordingly. In this way, we obtain the SED measurements over the entire 0.3-5[mu]m range in the most self-consistent manner. Using this SED catalog as the basis, we derive photometric redshifts and stellar masses for all the 9 million galaxies that span z = 0-0.8. This provides us an unprecedented statistics when deriving galaxy stellar mass functions (MFs) and GSMD over multiple redshift bins. Some preliminary results are discussed. As a by-product of our morphological template fitting process, an interesting population of objects called "WISE Optical Dropouts" ("WoDrops" for short) are discovered. These objects are significant detections in WISE data but are invisible in all the SDSS Stripe 82 data. Their nature remains a mystery up to this point. Among all possibilities, the only viable interpretation is that they are very high-mass galaxies with very high dust extinctions. To reveal their nature, future observations at larger facilities will be necessary.

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Local AGN survey (LASr): I. Galaxy sample, infrared colour selection, and predictions for AGN within 100 Mpc

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa766 ◽

2020 ◽

Vol 494 (2) ◽

pp. 1784-1816

Author(s):

D Asmus ◽

C L Greenwell ◽

P Gandhi ◽

P G Boorman ◽

J Aird ◽

...

Keyword(s):

Active Galactic Nuclei ◽

Galaxy Evolution ◽

Galactic Nuclei ◽

Wide Field ◽

X Ray ◽

Sky Survey ◽

Galaxy Sample ◽

Redshift Survey ◽

Infrared Survey

ABSTRACT To answer major questions on supermassive black hole (SMBH) and galaxy evolution, a complete census of SMBH growth, i.e. active galactic nuclei (AGN), is required. Thanks to all-sky surveys by the Wide-field Infrared Survey Explorer (WISE) and the Spectrum-Roentgen-Gamma (SRG) missions, this task is now feasible in the nearby Universe. We present a new survey, the Local AGN Survey (LASr), with the goal of identifying AGN unbiased against obscuration and determining the intrinsic Compton-thick (CT) fraction. We construct the most complete all-sky galaxy sample within 100 Mpc ($90{{\ \rm per\ cent}}$ completeness for log (M*/M⊙) ∼ 9.4), four times deeper than the current reference, the Two Micron All-Sky Survey Redshift Survey (2MRS), which misses ${\sim}20{{\ \rm per\ cent}}$ of known luminous AGN. These 49k galaxies serve as parent sample for LASr, called LASr-GPS. It contains 4.3k already known AGN, $\ge 82{{\ \rm per\ cent}}$ of these are estimated to have $L^\mathrm{nuc}(12\, \mu \mathrm{m})\lt 10^{42.3}$ erg s−1, i.e. are low-luminosity AGN. As a first method for identifying Seyfert-like AGN, we use WISE-based infrared colours, finding 221 galaxies at $L^\mathrm{nuc}(12\, \mu \mathrm{m})\ge 10^{42.3}$ erg s−1 to host an AGN at $90{{\ \rm per\ cent}}$ reliability. This includes 61 new AGN candidates and implies an optical type 2 fraction of 50–71 per cent. We quantify the efficiency of this technique and estimate the total number of AGN with $L^\mathrm{int}(\rm {2-10\,keV})\ge 10^{42}$ erg s−1 in the volume to be $362^{+145}_{-116}$ ($8.6^{+3.5}_{-2.8}\, \times$ 10−5 Mpc−3). X-ray brightness estimates indicate the CT fraction to be 40–55 per cent to explain the Swift non-detections of the infrared selected objects. One third of the AGN within 100 Mpc remain to be identified, and we discuss the prospects for the eROSITA all-sky survey to detect them.

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Near-Earth Asteroids on Archival Schmidt Plates

International Astronomical Union Colloquium ◽

10.1017/s0252921100021874 ◽

1995 ◽

Vol 148 ◽

pp. 170-173

Author(s):

R. H. McNaught ◽

D. I. Steel ◽

K. S. Russell ◽

G. V. Williams

Keyword(s):

Wide Field ◽

Schmidt Telescope ◽

Field Plate ◽

The Earth ◽

Routine Identification ◽

Scientific Results ◽

Near Earth Asteroids ◽

Asteroids And Comets

AbstractWe describe our routine identification of images of asteroids and comets on plates and films in the U.K. Schmidt Telescope archive. The asteroids of most interest to us are those which approach the Earth, and whenever such an object is found (by anyone) we perform backintegrations in order to determine whether the object may have been recorded on any UKST plate taken since 1973. In many cases the object is found (‘precovered’) and measured, allowing an accurate orbit to be determined soon after its discovery; other studies such as long-term dynamical investigations, or predictions of future close approaches to the Earth, are then possible. Similar programs using other wide-field plate archives are to be encouraged, since valuable scientific results may be derived.

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Warm Debris Disks with WISE and HST

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315006456 ◽

2015 ◽

Vol 10 (S314) ◽

pp. 175-178 ◽

Cited By ~ 1

Author(s):

Deborah Padgett ◽

Karl Stapelfeldt

Keyword(s):

Scattered Light ◽

Terrestrial Planets ◽

Wide Field ◽

Debris Disks ◽

Circumstellar Material ◽

Excess Emission ◽

Sky Survey ◽

Debris Disk ◽

Infrared Survey

AbstractUsing 22 μm data from the Wide Field Infrared Survey Explorer (WISE), we have completed a sensitive all-sky survey for debris disks in Hipparcos and Tycho catalog stars within 120 pc. This warm excess emission traces material in the circumstellar region likely to host terrestrial planets. Several hundred previously unknown debris disk candidates were identified. We are currently performing follow-up observations to characterize the stars, companions, and circumstellar material in these systems with a variety of facilities including Keck, Herschel, and HST. Thirteen WISE debris disks have been observed to date using HST/STIS coronagraphy. Five of these disks have been detected in scattered light. One is a large and highly asymmetric edge-on disk which appears to be both warped and bifurcated.

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AGN torus properties with WISE

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314003317 ◽

2013 ◽

Vol 9 (S304) ◽

pp. 56-60

Author(s):

Robert Nikutta ◽

Maia Nenkova ◽

Željko Ivezić ◽

Nicholas Hunt-Walker ◽

Moshe Elitzur

Keyword(s):

Color Space ◽

Sloan Digital Sky Survey ◽

Wide Field ◽

Sky Survey ◽

Very Large Database ◽

First Time ◽

Previous Identification ◽

Infrared Survey

AbstractThe Wide-field Infrared Survey Explorer (WISE) has scanned the entire sky with unprecedented sensitivity in four infrared bands, at 3.4, 4.6, 12, and 22 μm. The WISE Point Source Catalog contains more than 560 million objects, among them hundreds of thousands of galaxies with Active Nuclei (AGN). While type 1 AGN, owing to their bright and unobscured nature, are easy to detect and constitute a rather complete and unbiased sample, their type 2 counterparts, postulated by AGN unification, are not as straightforward to identify. Matching the WISE catalog with known QSOs in the Sloan Digital Sky Survey we confirm previous identification of the type 1 locus in the WISE color space. Using a very large database of the popular Clumpy torus models, we find the colors of the putative type 2 counterparts, and also, for the first time, predict their number vs. flux relation that can be expected to be observed in any given WISE color range. This will allow us to put statistically very significant constraints on the torus parameters. Our results are a successful test of the AGN unification scheme.

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A Census of the Stellar Populations in the Sco-Cen Complex*

The Astronomical Journal ◽

10.3847/1538-3881/ac35e2 ◽

2021 ◽

Vol 163 (1) ◽

pp. 24

Author(s):

K. L. Luhman

Keyword(s):

High Precision ◽

Stellar Populations ◽

Young Stars ◽

Initial Mass ◽

Wide Field ◽

The Third ◽

Sky Survey ◽

Data Release ◽

Mass Functions ◽

Infrared Survey

Abstract I have used high-precision photometry and astrometry from the early installment of the third data release of Gaia (EDR3) to perform a survey for members of the stellar populations within the Sco-Cen complex, which consist of Upper Sco, UCL/LCC, the V1062 Sco group, Ophiuchus, and Lupus. Among Gaia sources with σ π < 1 mas, I have identified 10,509 candidate members of those populations. I have compiled previous measurements of spectral types, Li equivalent widths, and radial velocities for the candidates, which are available for 3169, 1420, and 1740 objects, respectively. In a subset of candidates selected to minimize field star contamination, I estimate that the contamination is ≲1% and the completeness is ∼90% at spectral types of ≲M6–M7 for the populations with low extinction (Upper Sco, V1062 Sco, UCL/LCC). I have used that cleaner sample to characterize the stellar populations in Sco-Cen in terms of their initial mass functions, ages, and space velocities. For instance, all of the populations in Sco-Cen have histograms of spectral types that peak near M4–M5, which indicates that they share similar characteristic masses for their initial mass functions (∼0.15–0.2 M ⊙). After accounting for incompleteness, I estimate that the Sco-Cen complex contains nearly 10,000 members with masses above ∼0.01 M ⊙. Finally, I also present new estimates for the intrinsic colors of young stars and brown dwarfs (≲20 Myr) in bands from Gaia EDR3, the Two Micron All Sky Survey, the Wide-field Infrared Survey Explorer, and the Spitzer Space Telescope.

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From Discovery to Impact - Near Earth Asteroids

Geoinformatics FCE CTU ◽

10.14311/gi.8.5 ◽

2012 ◽

Vol 8 ◽

pp. 73-78

Author(s):

Miloš Tichý ◽

Michaela Honková ◽

Jana Tichá ◽

Michal Kočer

Keyword(s):

Solar System ◽

Current System ◽

Small Bodies ◽

Impact Site ◽

The Earth ◽

Near Earth Asteroids ◽

Near Earth Objects

The Near-Earth Objects (NEOs) are the most important of the small bodies of the solar system, having the capability of close approaches to the Earth and the chance to collide with the Earth. We present here the current system of discovery of these dangerous objects, standards for selecting useful and important targets for NEO follow-up astrometry, system of impact probabilities calculations, and also determination of impact site and evacuation area.

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