2018A proposals

We propose to address two outstanding questions concerning exoplanets, both requiring large new datasets: (1) What is the exoplanet mass/period distribution, in particular for the poorly-represented ``Hot Neptune`` and ``Warm Jupiter`` populations, and (2) Why are the orbital axes of some planets so strongly inclined to the rotational axes of their parent stars? To do this, we will combine intensive observations with the new LCO- NRES spectrograph network with discovery data from the Transiting Exoplanet Survey Satellite (TESS -- to be launched near the end of calendar 2017), and from existing space- and ground-based transiting planet discovery facilities.

Our proposed project will carry out all of LCO's observing commitments to the TESS mission, but will greatly extend the TESS sample in order to answer the above science questions, which are uniquely accessible to LCO-NRES. The project will run for 6 semesters, obtain repeated spectra of some 500 exoplanet host stars and use a total of 12,700 observing hours, about half of which will come from the LCO Key Project pool. Our main activities will be to bring NRES up to its full potential as a global observing system, to develop software tools to enhance its scientific productivity, to carry out and analyze the needed observations for our science program, and to publish our scientific and technical results promptly.

In 2017, the new near-IR Habitable-zone Planet Finder (HPF) spectrograph will begin surveying nearby mid-late M dwarfs for low-mass exoplanets. We propose to use the LCO network to acquire V- and i-band photometry of our HPF survey targets every night they are observable. These observations will facilitate the identification of rotation periods, magnetic cycles, and other activity phenomena, providing valuable insight into the magnetic fields of fully convective stars, and be crucial in the separation of Doppler exoplanet signals from activity-induced noise. Our targets are bright enough to be observed with any of the LCO telescopes, and distributed across the northern sky. Thus, our program takes maximal advantage of LCO`s flexibility, especially as the new northern and equatorial telescopes come online.

LCO is becoming a one-stop shop for exoplanet observations. With the deployment of NRES it will be capable of obtaining both RVs to measure the orbit and photometry to measure the transit, all using a robotic telescope network. This is especially useful for observations of transiting planet candidates, confirming their planetary nature and measuring their orbit and mass, along with studying the systems architecture. Such observations are currently a bottleneck due to the lack of sufficient observing resources. We will use LCO to observe transiting planets identified by the Kepler, K2, KELT, HAT- South, and TESS surveys. We have identified 4 observing activities where LCO will make a significant contribution: In Part I we will detect transiting warm Jupiters, to study the inflated gas giant planet conundrum. In Part II we will observe transiting systems showing transit timing variations, to look for small planets in wide orbits, beyond the reach of the RV method. In Part III we will observe planet candidates orbiting bright and quiet stars which once confirmed will become prime targets for detailed characterization. In Part IV we will observe transit candidates to check whether the transit signal seen in the survey data is in fact a false positive originating from a deep eclipse on a nearby star diluted with the target in the wide PSF of the survey instrument. Each part is independent of the rest while combined they will make LCO a leading player in the exoplanets field.

Current planet formation theories predict that planets with semi-major axes between 1-10 AU should be abundant, yet they lie beyond the detection limits of most planet finding techniques. To this day, this important region of planetary parameter space remains largely unexplored. Discovering them is critical in understanding the physical processes that drive planet formation. - We propose a 3-year gravitational microlensing Key Project to discover new exoplanets in the cold outer regions of planetary systems, including free-floating planets and, potentially, planets around stellar remnants. Previous microlensing programs were limited in their ability to characterize source stars and could not obtain uninterrupted 24/7 observational coverage. We propose a novel approach that combines a multi-wavelength survey with reactive follow-up observations, and which relies on the unique capabilities of the global Las Cumbres Observatory (LCO) network and its newly deployed wider-field cameras. - We will achieve enhanced sensitivity to planets with smaller masses (less than 10 MEarth) by placing better constraints on the spectral type of the source stars and by employing software that optimizes light curve coverage during the most planet-sensitive sections of the microlensing event. We will thus be able to better constrain the physical properties of these new planets exclusively based on LCO data.

We seek to use the LCO 2-m telescopes to obtain astrometric observations of Virtual Impactors (VIs), which are Near Earth Objects (NEOs) that have the potential to impact Earth in future years. One VI is very large (500–1200m in diameter) and, because of its size and destructive po- tential, warrants recovery and continued observation during the forthcoming apparition to improve knowledge of its orbit. The second VI is large (70–160m in diameter) and likely 100 times the mass of the Chelyabinsk object. With its recovery at ≥1 orbital periods from discovery, a greatly improved assessment of the Earth impact risk will be possible. Outcomes range from removing it from the VI list (the most likely outcome) to its confirmation as a VI with greatly improved orbital elements and Earth impact risk assessments by JPL and NEODyS.

Evidence is growing that core collapse in the most massive red supergiants might fail to explode the star and instead result in prompt black hole formation. In such a case, it is predicted that the loss of gravitational binding energy will result in a weak shock that unbinds the hydrogen envelope. With the high-cadence survey of the Zwicky Transient Facility we will have the survey speed to potentially discover the shock breakout associated with such a “failed” supernova. We propose LCO photometric follow-up of candidate events. This program has the potential to yield the first light curve of a failed supernova shock breakout and, when paired with other observations of the fainter, longer-lived recombination-powered transient expected to follow such an event, would provide strong evidence that we have indeed witnessed the birth of a black hole birth from stellar core-collapse.

The Fast and the Furious is a high-cadence survey in the Galactic Plane covering the full inner Plane visible from the northern hemisphere as part of observations of the Zwicky Transient Facility. The goal is to identify an unbiased sample of ultracompact binaries such as interacting AMCVn type binaries and detached white dwarf/He-star binaries with orbital periods below 2 hours. Our survey will provide a comprehensive census of short period variables and allow for a detailed population study of different classes of ultracompact binaries. Here we request a total of 64 hours with the LCO-1m telescopes and 16 hours with the LCO- 2m telescopes to obtain high signal to noise ratio follow-up lightcurves of the 10 most interesting systems (most compact, highest component masses) found in the Fast and the Furious survey. The individual lightcurves will allow us to measure the orbital period precisely and, in combination with spectroscopy, measure precise system parameters such as masses, inclination or radii.

Periodic variability in quasars has been predicted as an observational signature of supermassive black hole binaries (SMBHBs), which should be a common product of the hierarchy growth of galaxies. We have performed a systematic search in the Pan-STARRS1 Medium Deep Survey and identified a number of periodic quasar candidates with variations over > 1.5 cycles. We have been monitoring them with the Large Monolithic Imager at the Discovery Channel Telescope, since a long baseline is essential in order to break a false positive signal due to normal, stochastic quasar variability. Here we propose to continue and expand our imaging campaign with LCO. The proposed observations will be able to verify strong SMBHB candidates that are in the gravitational wave regime of orbital decay accessible to the Pulsar Timing Arrays and for the upcoming era of the Large Synoptic Survey Telescope.

Many open questions in supernova (SN) physics rely on the connection between core-collapse SNe and their massive progenitor stars. It is now possible to directly investigate SN progenitor systems, but only for the small fraction of nearby SNe with pre-explosion Hubble Space Telescope (HST) imaging. Therefore, each new discovery must be optimally exploited in order to obtain as much information as possible connecting SN and progenitor star. We propose to use the unique rapid response and monitoring capabilities of the LCO Global Telescope Network to investigate the early-time light curves and spectroscopic evolution of core-collapse SNe that have pre-explosion HST imaging. The early-time light curve is sensitive of the radius of the progenitor star, and we will use this information to produce an independent constraint on progenitor star systems.

We propose to continue our LCO followup program begun last semester of photometry and spectroscopy of newly discovered candidate cataclysmic variables (CVs) in current optical sky surveys (CRTS, MASTER, ASAS-SN), with particular emphasis on low luminosity, short period dwarf novae that have infrequent outbursts, related period bouncers and systems containing highly magnetic white dwarfs. These objects are crucial for understanding the nature of close binary evolution, particularly at the shortest orbital periods (60-90 min). In addition, the rare but important class of double-degenerate systems, potential progenitors of Type Ia SN are also potential candidates from these surveys. The primary goals are to obtain spectra to confirm the CV nature and delineate the object types, and obtain light curves to find the orbital periods, an essential key parameter to determine the evolutionary status. We need to accumulate large numbers to test population model predictions for angular momentum loss and evolution. We request further data for new objects continuously appearing in the surveys, using 3 hr continuous photometry (in g and r) for 2-3 objects/ month and spectra of about 4/month throughout the semester. We use larger telescope access by the PI and CoIs at APO, MDM, Caltech and SAAO to accomplish radial velocities of the most interesting targets determined by LCO. The next semester is especially important as ZTF commissioning will start in Nov while the main public survey will begin in Jan 2018, adding large numbers of candidates each month.

We request LCOGT data to support our ASAS-SN survey for Galactic novae. ASAS-SN surveys the Galactic plane and bulge every-other-night, and can, in principle, detect novae down to V ∼ 17 mag, provid- ing the first systematic survey for Galactic novae with well-defined selection effects. LCOGT will assist this effort in three ways: first, photometry will allow us to differentiate faint (V > 11 mag) novae from cataclysmic variable outbursts using colors. Second, FLOYDS spectroscopy will provide the prompt spectroscopic confirmation needed to trigger multi-wavelength campaigns to study the nova target. Finally, multi-band LCOGT photometry will allow us to measure high-quality bolometric light curves. These light curves will be compared with γ-ray data to assess the importance and prevalence of shocks in novae.

In this proposal, we are requesting 12 hours of time on 1-m telescopes and 3 hours of time on 2-m telescopes in the LCO network over 3 consecutive 24-hour periods in order to complete a project to quantify the change in the rotation period of the long-period comet C/2015 ER61 (PANSTARRS). This comet underwent an outburst in March 2017, and it is possible that the rotation period was altered as a result. Measuring the magnitude of this change will enable an estimation of the mass of total ejected material. Observations obtained in the 2015B and 2016A semesters with the LCO provide a pre-outburst, pre-perihelion rotation light curve of this comet; these observations, proposed almost 2 years later for December 2017/January 2018, will provide the post-outburst, post-perihelion rotation light curve for comparison. Based on Monte Carlo simulations, we will be able to detect a potential difference between the two rotation periods of up to 40 minutes at the 3-σ level.

This project is to obtain deep U images of a unique sample of LSB dwarfs/disks galaxies. While the UV luminosity of most galaxies is strongly tied to the current SFR of a galaxy, recent studies have questioned the tight correlation between SFR from Hα and the UV (which has enormous impact on SFR evolution studies). In particular, Meurer et al. (2009) have stated that there is a strong correlation in FHα/fUV with surface brightness, morphology and dynamical mass (i.e., the ratio is part of a larger family of scaling relations). This result is at odds with our HST imaging of several LSB galaxies and we suspect the range of surface brightness was inadequate to make such claims. Therefore, we propose to make Johnson U observations of a unique sample of LSB galaxies (truly LSB, not intermediate as presented in GALEX papers), ranging in baryonic mass, size, gas fraction and Hα SFR. All the targets proposed herein have a complete set of optical, Hα and Spitzer imaging. These new UV observations will provide a spatial analysis of UV structure and luminosity of LSB galaxies with direct comparison to the optical and near-IR images for the same objects. This is the last missing link in understanding the star formation history and stellar populations of these important galaxies.

Long-Gamma ray bursts can be observed up to the very first epoch of stellar formation (z 20). Unfortunately, their rapidly fading optical/NIR counterparts make it very difficult to obtain accurate information about their progenitors (e.g. well sampled multiband lightcurves) and their distance (e.g. spectroscopic redshift). With this proposal we intend to use the LCO network observatory in order to identify optical/NIR counterparts and provide preliminary information about their high redshift nature (via R-I color and FLOYDS spectroscopy). LCO rapid ToOs will enable the inves- tigation the most interesting objects that may be produced by the first generation of stars. Our collaboration includes also the possibility to use other facilities (like the DCT and RATIR), to further studies the primordial interstellar and intergalactic medium.

We propose to observe the optical counterparts of two black hole binary systems. The scientific goals are 1) to refine the system inclination and mass of the black hole; 2) to understand the accretion flow in the quiescent state; 3) to establish templates for the identification of black hole systems in quiescence in future time domain surveys. Point 3 is of particular importance in the LIGO era. The demographics of black hole binaries are currently subject to an intense selection effect because they are identified initially through their X-ray outbursts. Identification by optical properties would be a significant improvement in this regard.

Our understanding of star formation in the solar neighborhood has recently been turned upside down. Our analysis of the 3D spatial distribution of OB stars within 500pc from the Sun revealed large stream-like structures – the ”Blue Streams” – covering several hundreds of parsec and about 70 Myr of continuous star formation history (Bouy & Alves, 2015). Follow-up spectroscopic observations of one of them, the Orion Blue Stream, not only allow us to confirm the existence of this structure, but also led to an even more surprising discovery: the Orion Blue Stream displays an extremely low velocity dispersion (<0.2km/s) over 100 pc, which cannot be explained by current models and theories of star formation. What is the origin of the blue streams? What is their role in the star formation on galactic scale? We propose to answer these pressing questions by obtaining precise radial velocity, Teff and log g measurements with the echelle spectrographs of the LCO network for all the known OB star members of the other major nearby blue stream: Sco-CMa. These measurements will have an immense legacy value, providing radial velocities an order of magnitude more accurate than Gaia for a genetically related population of massive stars covering a contiguous region of almost 350pc and 70 Myr of star formation propagation. Together with existing multi wavelength photometry (from optical to mid-IR, already at hand) and with the accurate Gaia proper motions and parallaxes (to be delivered in spring 2018, almost together with the proposed observations), these measurements will allow the construction of the most accurate star formation history of the Solar neighborhood, on spatial (350 pc) and time (70 Myr) scales never systematically probed before, and making the missing connection between star formation studies on local and extragalactic scales.

We propose a joint LCO-Zwicky Transient Facility (ZTF) ToO program to investigate young, relativistic stellar explosions and supernovae (SNe) on timescales of hours to days. High-cadence ZTF observations over large areas will regularly uncover very young transients. For the most common stellar explosions, supernovae (SNe), LCO will prove critical in solving the long-standing problem of mapping between SN types and progenitor systems. For SNe Ia, early UV/optical light curves are sensitive to radioactive-56Ni mixing in the ejecta and thereby shed light on explosion mechanism(s). These observations will help constrain the fraction of SNe Ia that come from single degenerate vs. double degerate binary progenitors. For core collapse SNe, LCO will help map SN types to progenitor properties (radius, mass-loss history), while also probing the unique CSM seen around some massive stars. Finally, there are classes of relativistic explosions predicted to exist but never found: dirty fireballs and orphan afterglows. This LCO-ZTF program has the capability to discover these events for the first time.

We propose to observe the mutual events between the two members of the binary Trojan asteroid Patroclus-Menoetius with LCO imaging to constrain their orbit, which will affect design decisions for NASA’s Lucy mission to the Jupiter Trojans, and to study their sizes and surface properties. During their mutual event season, Patroclus and Menoetius take turns eclipsing or occulting one another every 2.14 days. Mutual events can improve orbits, constrain limb-darkening, reveal photometric properties, and map heterogeneities. The Patroclus-Menoetius mutual event season occurs twice every 12-year orbit, and the season in 2017-2019 is the last one that can affect the Lucy design.

The gravitational microlensing planet detection method has two main strengths. It is sensitive to planets down to low masses beyond the snow line, where giant planets can form most efficiently, and it is sensitive to planetary systems in different stellar environments, from the Solar neighborhood to the Galactic bulge. Recent improvements in the capabilities of gravitational microlensing search efforts with the OGLE-IV survey, the Korean Microlensing Telescope Network, and the Las Cumbres Observatory (LCO) Global Telescope Network have significantly improved the microlensing exoplanet discovery rate. The Spitzer and K2 microlensing parallax programs have improved our ability to determine masses and distances for planetary systems in the Galactic disk. However, somewhat by accident, our ability to determine the masses and distances to microlensing planetary systems in the Galactic bulge decreased in recent years. We propose use the rapid high magnification alert capability of the MOA-II survey to take advantage of the rapid alert response capability of the LCO network significantly to increase the discovery rate of planetary systems that can be proven to reside in the Galactic bulge.

The proposed observations will provide high-cadence lightcurves of 3 cometary outbursts, enabling us to estimate dust expansion speeds, total dust mass, and total kinetic energy for each event. We will use this program to prototype an early warning system to detect small outbursts, and to activate rapid follow-up observations.

Transiting planets around bright stars are key objects for exploring the physical properties of planets outside the Solar System. The US-based HATNet and HATSouth surveys are leading efforts for discovering and characterizing these planets. Candidate planets that are identified by the surveys must be confirmed through high-precision photometric and spectroscopic follow-up observations. Here we propose to use the Sinistro imagers on the LCO 1m network to carry out these observations for dozens of candidates, which will contribute to the discovery and characterization of ∼ 18 new well characterized planets. This effort will focus on confirming planets around M dwarfs, Neptune-size planets, and long period planets, with the goal of expanding the sample of such objects known around bright stars. The planets discovered through this effort will be amenable to detailed follow-up studies, such as transmission spectroscopy with JWST.

We propose accretion-disk reverberation mapping (RM) of 5 quasars using the LCO 2m to add r and z optical photometry to our approved HST UV monitoring campaign. There exist only 4 previous low-luminosity Seyfert AGNs with UV/optical RM accretion-disk sizes: in contrast, our 5 quasars span an order of magnitude higher accretion rate and have accurate BH masses from SDSS-RM. The combined UV-optical RM observations will directly probe the accretion-rate dependence of the inner accretion disk, where significant structural changes have been suggested by theory and previous indirect observations. Our scheduled 32-orbit HST UV campaign will only succeed with the rz optical monitoring proposed here. We use simulations to establish the 186-hr observing design, using a daily cadence from Feb 1 – May 20 to accurately measure UV-optical continuum lags and accretion-disk structure. The combined HST-LCO monitoring campaign will enable critical new measurements of accretion-disk structure during the rapid accretion mode that dominates black hole growth.

The magnetic activity of the Sun becomes stronger and weaker over roughly an 11-year cycle. Decades of observations from Mount Wilson and Lowell revealed that other stars also show regular activity cycles, and identified two distinct relationships between the length of the cycle and the rotation rate of the star. Neither of these relationships correctly describe the properties of the Sun, a peculiarity that demands further investigation. Recent work suggests that the Sun’s rotation rate and magnetic field may be in a transitional phase that occurs in all middle-aged stars, but additional observations are needed to test this hypothesis. We propose to begin long-term monitoring of Ca ii H and K emission for a sample of 34 bright stars with known rotation rates (Prot < 22 days), to identify the short activity cycles (Pcyc < 5 years) that are precursors of the 11-year solar cycle. For most of these targets, asteroseismic masses and ages are soon expected from the Transiting Exoplanet Survey Satellite (TESS), currently scheduled for launch in March 2018.

The ability to monitor galactic novae at high cadence is revealing new puzzles about just how white dwarf stars explode and lose mass. High cadence absorption line spectroscopy shows that the mass loss in many novae is highly complex. High cadence, high resolution spectroscopy may let us resolve the origin of absorption systems; correlations with OIR photometry are revealing insights into the physical processes. This is a ToO program. We request a total of 50 hours (5 nights) with LCO/NRES to obtain a high-cadence (nightly or better) sequence of synoptic spectra of the next bright galactic novae.

We propose imaging of PSR J1311-3430, a remarkable ultra-short period system with a millisecond pulsar evaporating its sub-stellar companion. The observation targets recently discovered X-ray/optical flares which probe eruptive processes in the intrabinary shock or on the heated companion surface. Our planned LCO observations provide near-continuous coverage in two filters during two proposed XMM-Newton integrations (60ks and 40ks), ideally scheduled in early 18A. If the XMM observations are delayed we request that at least a 60ks observation be completed in 18A, measuring flare statistics and establishing the color sensitivity.

We propose to photometrically characterize the population of stripped-envelope supernovae (SESNe) discovered by the Zwicky Transient Facility (ZTF) during science commissioning and the first semester of operations in 2018. The dataset will be used, in combination with semi-analytical and/or hydrodynamical modeling, in order to understand the nature of the progenitor stars that give rise to SESNe. In particular, we propose to collect u-band photometry around maximum light of a large amount of objects, which will allow us to constrain the host extinction and bolometric luminosity in an unprecedented way.

Binarity in Carbon-enhanced metal-poor stars

Calibrating Young Stellar Models with Dynamical Masses in the Gaia Era

ANU contribution to Transiting Exoplanets key project.

ANU contribution to Global Supernova key project.

High-cadence photometry of a young M+M dwarf eclipsing binary in the 32 Ori Moving Group