arXiv subjects

Jason Surace

Publications and source records attributed to Jason Surace.

At least 55 records · Page 3Linked to original sources

arXiv2016

Why are rapidly rotating M dwarfs in the Pleiades so (infra)red? New period measurements confirm rotation-dependent color offsets from the cluster sequence

Stellar rotation periods measured in open clusters have proved to be extremely useful for studying stars' angular momentum content and rotationally driven magnetic activity, which are both age- and mass-dependent processes. While period measurements have been obtained for hundreds of solar-mass members of the Pleiades, period measurements exist for only a few low-mass ($<$0.5 M$_{\odot}$) members of this key laboratory for stellar evolution theory. To fill this gap, we report rotation periods for 132 low-mass Pleiades members (including nearly 100 with M $\leq$ 0.45 M$_{\odot}$), measured from photometric monitoring of the cluster conducted by the Palomar Transient Factory in late 2011 and early 2012. These periods extend the portrait of stellar rotation at 125 Myr to the lowest-mass stars and re-establish the Pleiades as a key benchmark for models of the transport and evolution of stellar angular momentum. Combining our new rotation periods with precise BVIJHK photometry reported by Stauffer et al. and Kamai et al., we investigate known anomalies in the photometric properties of K and M Pleiades members. We confirm the correlation detected by Kamai et al. between a star's rotation period and position relative to the main sequence in the cluster's color-magnitude diagram. We find that rapid rotators have redder (V-K) colors than slower rotators at the same V, indicating that rapid and slow rotators have different binary frequencies and/or photospheric properties. We find no difference in the photometric amplitudes of rapid and slow rotators, indicating that asymmetries in the longitudinal distribution of starspots do not scale grossly with rotation rate.

astro-ph.SR↗

arXiv2015

The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Quasar Target Selection

As part of the Sloan Digital Sky Survey IV the extended Baryon Oscillation Spectroscopic Survey (eBOSS) will improve measurements of the cosmological distance scale by applying the Baryon Acoustic Oscillation (BAO) method to quasar samples. eBOSS will adopt two approaches to target quasars over 7500 sq. deg. First, a "CORE" quasar sample will combine optical selection in ugriz using a likelihood-based routine called XDQSOz, with a mid-IR-optical color-cut. eBOSS CORE selection (to g < 22 OR r < 22) should return ~ 70 quasars per sq. deg. at redshifts 0.9 < z < 2.2 and ~7 z > 2.1 quasars per sq. deg. Second, a selection based on variability in multi-epoch imaging from the Palomar Transient Factory should recover an additional ~3-4 z > 2.1 quasars per sq. deg. to g < 22.5. A linear model of how imaging systematics affect target density recovers the angular distribution of eBOSS CORE quasars over 96.7% (76.7%) of the SDSS North (South) Galactic Cap area. The eBOSS CORE quasar sample should thus be sufficiently dense and homogeneous over 0.9 < z < 2.2 to yield the first few-percent-level BAO constraint near z~1.5. eBOSS quasars at z > 2.1 will be used to improve BAO measurements in the Lyman-alpha Forest. Beyond its key cosmological goals, eBOSS should be the next-generation quasar survey, comprising > 500,000 new quasars and > 500,000 uniformly selected spectroscopically confirmed 0.9 < z < 2.2 quasars. At the conclusion of eBOSS, the SDSS will have provided unique spectra of over 800,000 quasars.

astro-ph.CO↗

arXiv2015

The Star-Formation History of BCGs to z = 1.8 from the SpARCS/SWIRE Survey: Evidence for significant in-situ star formation at high-redshift

We present the results of a MIPS-24um study of the Brightest Cluster Galaxies (BCGs) of 535 high-redshift galaxy clusters. The clusters are drawn from the Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS), which effectively provides a sample selected on total stellar mass, over 0.2 < z < 1.8 within the Spitzer Wide-Area Infrared Extragalactic (SWIRE) Survey fields. 20%, or 106 clusters have spectroscopically confirmed redshifts, and the rest have redshifts estimated from the color of their red sequence. A comparison with the public SWIRE images detects 125 individual BCGs at 24um > 100uJy, or 23%. The luminosity-limited detection rate of BCGs in similar richness clusters (Ngal> 12) increases rapidly with redshift. Above z ~ 1, an average of ~20\% of the sample have 24um-inferred infrared luminosities of LIR > 10^12 Lsun, while the fraction below z ~ 1 exhibiting such luminosities is < 1 \%. The Spitzer-IRAC colors indicate the bulk of the 24um-detected population is predominantly powered by star formation, with only 7/125 galaxies lying within the color region inhabited by Active Galactic Nuclei (AGN). Simple arguments limit the star-formation activity to several hundred million years and this may therefore be indicative of the timescale for AGN feedback to halt the star formation. Below redshift z ~ 1 there is not enough star formation to significantly contribute to the overall stellar mass of the BCG population, and therefore BCG growth is likely dominated by dry-mergers. Above z~ 1, however, the inferred star formation would double the stellar mass of the BCGs and is comparable to the mass assembly predicted by simulations through dry mergers. We cannot yet constrain the process driving the star formation for the overall sample, though a single object studied in detail is consistent with a gas-rich merger.

astro-ph.GA↗

arXiv2015

An Extreme Starburst in Close Proximity to the Central Galaxy of a Rich Galaxy Cluster at z=1.7

We have discovered an optically rich galaxy cluster at z=1.7089 with star formation occurring in close proximity to the central galaxy. The system, SpARCS104922.6+564032.5, was detected within the Spitzer Adaptation of the red-sequence Cluster Survey, (SpARCS), and confirmed through Keck-MOSFIRE spectroscopy. The rest-frame optical richness of Ngal(500kpc) = 30+/-8 implies a total halo mass, within 500kpc, of ~3.8+/-1.2 x 10^14 Msun, comparable to other clusters at or above this redshift. There is a wealth of ancillary data available, including Canada-France-Hawaii Telescope optical, UKIRT-K, Spitzer-IRAC/MIPS, and Herschel-SPIRE. This work adds submillimeter imaging with the SCUBA2 camera on the James Clerk Maxwell Telescope and near-infrared imaging with the Hubble Space Telescope (HST). The mid/far-infrared (M/FIR) data detect an Ultra-luminous Infrared Galaxy spatially coincident with the central galaxy, with LIR = 6.2+/-0.9 x 10^12 Lsun. The detection of polycyclic aromatic hydrocarbons (PAHs) at z=1.7 in a Spitzer-IRS spectrum of the source implies the FIR luminosity is dominated by star formation (an Active Galactic Nucleus contribution of 20%) with a rate of ~860+/-30 Msun/yr. The optical source corresponding to the IR emission is likely a chain of of > 10 individual clumps arranged as "beads on a string" over a linear scale of 66 kpc. Its morphology and proximity to the Brightest Cluster Galaxy imply a gas-rich interaction at the center of the cluster triggered the star formation. This system indicates that wet mergers may be an important process in forming the stellar mass of BCGs at early times.

astro-ph.GA↗

arXiv2015

Search for precursor eruptions among Type IIb supernovae

The progenitor stars of several Type IIb supernovae (SNe) show indications for extended hydrogen envelopes. These envelopes might be the outcome of luminous energetic pre-explosion events, so-called precursor eruptions. We use the Palomar Transient Factory (PTF) pre-explosion observations of a sample of 27 nearby Type IIb SNe to look for such precursors during the final years prior to the SN explosion. No precursors are found when combining the observations in 15-day bins, and we calculate the absolute-magnitude-dependent upper limit on the precursor rate. At the 90% confidence level, Type IIb SNe have on average $<0.86$ precursors as bright as absolute $R$-band magnitude $-14$ in the final 3.5 years before the explosion and $<0.56$ events over the final year. In contrast, precursors among SNe IIn have a $\gtrsim 5$ times higher rate. The kinetic energy required to unbind a low-mass stellar envelope is comparable to the radiated energy of a few-weeks-long precursor which would be detectable for the closest SNe in our sample. Therefore, mass ejections, if they are common in such SNe, are radiatively inefficient or have durations longer than months. Indeed, when using 60-day bins a faint precursor candidate is detected prior to SN 2012cs ($\sim2$% false-alarm probability). We also report the detection of the progenitor of SN 2011dh which does not show detectable variability over the final two years before the explosion. The suggested progenitor of SN 2012P is still present, and hence is likely a compact star cluster, or an unrelated object.

astro-ph.HE↗

arXiv2015

Asteroid Spin-Rate Study using the Intermediate Palomar Transient Factory

Two dedicated asteroid rotation-period surveys have been carried out using data taken on January 6-9 and February 20-23 of 2014 by the Intermediate Palomar Transient Factory (iPTF) in the $R$~band with $\sim 20$-min cadence. The total survey area covered 174~deg$^2$ in the ecliptic plane. Reliable rotation periods for 1,438 asteroids are obtained from a larger data set of 6,551 mostly main-belt asteroids, each with $\geq 10$~detections. Analysis of 1751, PTF based, reliable rotation periods clearly shows the "spin barrier" at $\sim 2$~hours for "rubble-pile" asteroids. We also found a new large-sized super-fast rotator, 2005 UW163 (Chang et al., 2014), and other five candidates as well. Our spin-rate distributions of asteroids with $3 < D < 15$~km shows number decrease when frequency greater than 5 rev/day, which is consistent to that of the Asteroid Light Curve Database (LCDB, Warner et al., 2009) and the result of (Masiero et al., 2009). We found the discrepancy in the spin-rate distribution between our result and (Pravec et al., 2008, update 2014-04-20) is mainly from asteroids with $Δm < 0.2$ mag that might be primarily due to different survey strategies. For asteroids with $D \leq 3$~km, we found a significant number drop at $f = 6$ rev/day. The YORP effect timescale for small-sized asteroid is shorter that makes more elongate objets spun up to reach their spin-rate limit and results in break-up. The K-S test suggests a possible difference in the spin-rate distributions of C- and S-type asteroids. We also find that C-type asteroids have a smaller spin-rate limit than the S-type, which agrees with the general sense that the C-type has lower bulk density than the S-type.

astro-ph.EP↗

arXiv2015

Strong Ultraviolet Pulse From a Newborn Type Ia Supernova

Type Ia supernovae are destructive explosions of carbon oxygen white dwarfs. Although they are used empirically to measure cosmological distances, the nature of their progenitors remains mysterious, One of the leading progenitor models, called the single degenerate channel, hypothesizes that a white dwarf accretes matter from a companion star and the resulting increase in its central pressure and temperature ignites thermonuclear explosion. Here we report observations of strong but declining ultraviolet emission from a Type Ia supernova within four days of its explosion. This emission is consistent with theoretical expectations of collision between material ejected by the supernova and a companion star, and therefore provides evidence that some Type Ia supernovae arise from the single degenerate channel.

astro-ph.SR↗

arXiv2015

Asteroid lightcurves from the Palomar Transient Factory survey: Rotation periods and phase functions from sparse photometry

We fit 54,296 sparsely-sampled asteroid lightcurves in the Palomar Transient Factory to a combined rotation plus phase-function model. Each lightcurve consists of 20+ observations acquired in a single opposition. Using 805 asteroids in our sample that have reference periods in the literature, we find the reliability of our fitted periods is a complicated function of the period, amplitude, apparent magnitude and other attributes. Using the 805-asteroid ground-truth sample, we train an automated classifier to estimate (along with manual inspection) the validity of the remaining 53,000 fitted periods. By this method we find 9,033 of our lightcurves (of 8,300 unique asteroids) have reliable periods. Subsequent consideration of asteroids with multiple lightcurve fits indicate 4% contamination in these reliable periods. For 3,902 lightcurves with sufficient phase-angle coverage and either a reliably-fit period or low amplitude, we examine the distribution of several phase-function parameters, none of which are bimodal though all correlate with the bond albedo and with visible-band colors. Comparing the theoretical maximal spin rate of a fluid body with our amplitude versus spin-rate distribution suggests that, if held together only by self-gravity, most asteroids are in general less dense than 2 g/cm$^3$, while C types have a lower limit of between 1 and 2 g/cm$^3$, in agreement with previous density estimates. For 5-20km diameters, S types rotate faster and have lower amplitudes than C types. If both populations share the same angular momentum, this may indicate the two types' differing ability to deform under rotational stress. Lastly, we compare our absolute magnitudes and apparent-magnitude residuals to those of the Minor Planet Center's nominal $G=0.15$, rotation-neglecting model; our phase-function plus Fourier-series fitting reduces asteroid photometric RMS scatter by a factor of 3.

astro-ph.EP↗

arXiv2014

Searching for Be Stars in the Open Cluster NGC 663

We present Be star candidates in the open cluster NGC\,663, identified by H$α$ imaging photometry with the Palomar Transient Factory Survey, as a pilot program to investigate how the Be star phenomena, the emission spectra, extended circumstellar envelopes, and fast rotation, correlate with massive stellar evolution. Stellar membership of the candidates was verified by 2MASS magnitudes and colors, and by proper motions. We discover 4 new Be stars and exclude one known Be star from being a member due to its inconsistent proper motions. The fraction of Be stars to member stars [N(Be)/N(members)] in NGC\,663 is 3.5\%. The spectral type of the 34 Be stars in NGC\,663 shows bimodal peaks at B0--B2 and B5--B7, which is consistent with the statistics in most star clusters. Additionally, we also discover 23 emission-line stars of different types, including non-member Be stars, dwarfs, and giants.

astro-ph.GA↗

arXiv2014

Long-term Photometric Behavior of Outbursting AM CVn Systems

The AM CVn systems are a class of He-rich, post-period minimum, semi-detached, ultra-compact binaries. Their long-term light curves have been poorly understood due to the few systems known and the long (hundreds of days) recurrence times between outbursts. We present combined photometric light curves from the LINEAR, CRTS, and PTF synoptic surveys to study the photometric variability of these systems over an almost 10 yr period. These light curves provide a much clearer picture of the outburst phenomena that these systems undergo. We characterize the photometric behavior of most known outbursting AM CVn systems and establish a relation between their outburst properties and the systems' orbital periods. We also explore why some systems have only shown a single outburst so far and expand the previously accepted phenomenological states of AM CVn systems. We conclude that the outbursts of these systems show evolution with respect to the orbital period, which can likely be attributed to the decreasing mass transfer rate with increasing period. Finally, we consider the number of AM CVn systems that should be present in modeled synoptic surveys.

astro-ph.SR↗

arXiv2014

The hydrogen-poor superluminous supernova iPTF13ajg and its host galaxy in absorption and emission

We present imaging and spectroscopy of a hydrogen-poor superluminous supernova (SLSN) discovered by the intermediate Palomar Transient Factory: iPTF13ajg. At a redshift of z=0.7403, derived from narrow absorption lines, iPTF13ajg peaked at an absolute magnitude M(u,AB)=-22.5, one of the most luminous supernovae to date. The uBgRiz light curves, obtained with the P48, P60, NOT, DCT, and Keck telescopes, and the nine-epoch spectral sequence secured with the Keck and the VLT (covering 3 rest-frame months), are tied together photometrically to provide an estimate of the flux evolution as a function of time and wavelength. The observed bolometric peak luminosity of iPTF13ajg is 3.2x10^44 erg/s, while the estimated total radiated energy is 1.3x10^51 erg. We detect narrow absorption lines of Mg I, Mg II, and Fe II, associated with the cold interstellar medium in the host galaxy, at two different epochs with X-shooter at the VLT. From Voigt-profile fitting, we derive the column densities log N(Mg I)=11.94+-0.06, log N(Mg II)=14.7+-0.3, and log N(Fe II)=14.25+-0.10. These column densities, as well as the Mg I and Mg II equivalent widths of a sample of hydrogen-poor SLSNe taken from the literature, are at the low end of those derived for gamma-ray bursts (GRBs), whose progenitors are also thought to be massive stars. This suggests that the environments of SLSNe and GRBs are different. From the nondetection of Fe II fine-structure absorption lines, we derive a strict lower limit on the distance between the supernova and the narrow-line absorbing gas of 50 pc. No host-galaxy emission lines are detected, leading to an upper limit on the unobscured star-formation rate of SFR([OII])<0.07 Msun/yr. Late-time imaging shows the host galaxy of iPTF13ajg to be faint, with g(AB)~27.0 and R(AB)>=26.0 mag, which roughly corresponds to M(B,Vega) >~ -17.7 mag. [abridged]

astro-ph.HE↗

arXiv2014

The FUV to Near-IR Morphologies of Luminous Infrared Galaxies in the GOALS Sample

We compare the morphologies of a sample of 20 LIRGs from the Great Observatories All-sky LIRG Survey (GOALS) in the FUV, B, I and H bands, using the Gini (G) and M20 parameters to quantitatively estimate the distribution and concentration of flux as a function of wavelength. HST images provide an average spatial resolution of ~80 pc. While our LIRGs can be reliably classified as mergers across the entire range of wavelengths studied here, there is a clear shift toward more negative M20 (more bulge-dominated) and a less significant decrease in G values at longer wavelengths. We find no correlation between the derived FUV G-M20 parameters and the global measures of the IR to FUV flux ratio, IRX. Given the fine resolution in our HST data, this suggests either that the UV morphology and IRX are correlated on very small scales, or that the regions emitting the bulk of the IR emission emit almost no FUV light. We use our multi-wavelength data to simulate how merging LIRGs would appear from z~0.5-3 in deep optical and near-infrared images such as the HUDF, and use these simulations to measure the G-M20 at these redshifts. Our simulations indicate a noticeable decrease in G, which flattens at z >= 2 by as much as 40%, resulting in mis-classifying our LIRGs as disk-like, even in the rest-frame FUV. The higher redshift values of M20 for the GOALS sources do not appear to change more than about 10% from the values at z~0. The change in G-M20 is caused by the surface brightness dimming of extended tidal features and asymmetries, and also the decreased spatial resolution which reduced the number of individual clumps identified. This effect, seen as early as z~0.5, could easily lead to an underestimate of the number of merging galaxies at high-redshift in the rest-frame FUV.

astro-ph.GA↗

arXiv2014

A New Large Super-Fast Rotator: (335433) 2005 UW163

Asteroids of size larger than 150 m generally do not have rotation periods smaller than 2.2 hours. This spin cutoff is believed to be due to the gravitationally bound rubble-pile structures of the asteroids. Rotation with periods exceeding this critical value will cause asteroid breakup. Up until now, only one object, 2001 OE84, has been found to be an exception to this spin cutoff. We report the discovery of a new super-fast rotator, (335433) 2005 UW163, spinning with a period of 1.290 hours and a lightcurve variation of $r'\sim0.8$ mag from the observations made at the P48 telescope and the P200 telescope of the Palomar Observatory. Its $H_{r'} = 17.69 \pm 0.27$ mag and multi-band colors (i.e., $g'-r' = 0.68\pm0.03$ mag, $r'-i' = 0.19\pm0.02$ mag and SDSS $i-z = -0.45$ mag) show it is a V-type asteroid with a diameter of $0.6 +0.3/-0.2$ km. This indicates (335433) 2005 UW163 is a super-fast rotator beyond the regime of the small monolithic asteroid.

astro-ph.EP↗

arXiv2014

IPAC Image Processing and Data Archiving for the Palomar Transient Factory

The Palomar Transient Factory (PTF) is a multi-epochal robotic survey of the northern sky that acquires data for the scientific study of transient and variable astrophysical phenomena. The camera and telescope provide for wide-field imaging in optical bands. In the five years of operation since first light on December 13, 2008, images taken with Mould-R and SDSS-g' camera filters have been routinely acquired on a nightly basis (weather permitting), and two different H-alpha filters were installed in May 2011 (656 nm and 663 nm). The PTF image-processing and data-archival program at the Infrared Processing and Analysis Center (IPAC) is tailored to receive and reduce the data, and, from it, generate and preserve astrometrically and photometrically calibrated images, extracted source catalogs, and coadded reference images. Relational databases have been deployed to track these products in operations and the data archive. The fully automated system has benefited by lessons learned from past IPAC projects and comprises advantageous features that are potentially incorporable into other ground-based observatories. Both off-the-shelf and in-house software have been utilized for economy and rapid development. The PTF data archive is curated by the NASA/IPAC Infrared Science Archive (IRSA). A state-of-the-art custom web interface has been deployed for downloading the raw images, processed images, and source catalogs from IRSA. Access to PTF data products is currently limited to an initial public data release (M81, M44, M42, SDSS Stripe 82, and the Kepler Survey Field). It is the intent of the PTF collaboration to release the full PTF data archive when sufficient funding becomes available.

astro-ph.IM↗

arXiv2014

Slow-Speed Supernovae from the Palomar Transient Factory: Two Channels

Since the discovery of the unusual prototype SN 2002cx, the eponymous class of low-velocity, hydrogen-poor supernovae has grown to include at most another two dozen members identified from several heterogeneous surveys, in some cases ambiguously. Here we present the results of a systematic study of 1077 hydrogen-poor supernovae discovered by the Palomar Transient Factory, leading to nine new members of this peculiar class. Moreover we find there are two distinct subclasses based on their spectroscopic, photometric, and host galaxy properties: The "SN 2002cx-like" supernovae tend to be in later-type or more irregular hosts, have more varied and generally dimmer luminosities, have longer rise times, and lack a Ti II trough when compared to the "SN 2002es-like" supernovae. None of our objects show helium, and we counter a previous claim of two such events. We also find that these transients comprise 5.6+17-3.7% (90% confidence) of all SNe Ia, lower compared to earlier estimates. Combining our objects with the literature sample, we propose that these subclasses have two distinct physical origins.

astro-ph.HE↗

arXiv2014

313 new asteroid rotation periods from Palomar Transient Factory observations

A new asteroid rotation period survey have been carried out by using the Palomar Transient Factory (PTF). Twelve consecutive PTF fields, which covered an area of 87 deg$^2$ in the ecliptic plane, were observed in $R$ band with a cadence of $\sim$20 min during February 15--18, 2013. We detected 2500 known asteroids with a diameter range of 0.5 km $\leq D \leq$ 200 km. Of these, 313 objects had highly reliable rotation periods and exhibited the "spin barrier" at $\sim2$ hours. In contrast to the flat spin rate distribution of the asteroids with 3 km $\leq D \leq$ 15 km shown by Pravec et al. (2008), our results deviated somewhat from a Maxwellian distribution and showed a decrease at the spin rate greater than 5 rev/day. One super-fast-rotator candidate and two possible binary asteroids were also found in this work.

astro-ph.EP↗

arXiv2014

An Accreting White Dwarf near the Chandrasekhar Limit in the Andromeda Galaxy

The iPTF detection of the most recent outburst of the recurrent nova system RX J0045.4+4154 in the Andromeda Galaxy has enabled the unprecedented study of a massive ($M>1.3\ M_\odot$) accreting white dwarf (WD). We detected this nova as part of the near daily iPTF monitoring of M31 to a depth of $R\approx 21$\,mag and triggered optical photometry, spectroscopy and soft X-ray monitoring of the outburst. Peaking at an absolute magnitude of $M_R=-6.6$ mag, and with a decay time of 1 mag per day, it is a faint and very fast nova. It shows optical emission lines of He/N and expansion velocities of 1900 to 2600 km s$^{-1}$ 1--4 days after the optical peak. The {\it Swift} monitoring of the X-ray evolution revealed a supersoft source (SSS) with $kT_{\rm eff}\approx 90-110\ {\rm eV}$ that appeared within 5 days after the optical peak, and lasted only 12 days. Most remarkably, this is not the first event from this system, rather it is a recurrent nova with a time between outbursts of approximately 1 year, the shortest known. Recurrent X-ray emission from this binary was detected by ROSAT in 1992 and 1993, and the source was well characterized as a $M>1.3\ M_\odot$ WD SSS. Based on the observed recurrence time between different outbursts, the duration and effective temperature of the SS phase, MESA models of accreting WDs allow us to constrain the accretion rate to $\dot M>1.7\times10^{-7}\ {M_{\odot}\ {\rm yr}}^{-1}$ and WD mass $>1.30\ M_{\odot}$. If the WD keeps $30\%$ of the accreted material, it will take less than a Myr to reach core densities high enough for carbon ignition (if made of C/O) or electron capture (if made of O/Ne) to end the binary evolution.

astro-ph.SR↗

arXiv2014

PTF1 J191905.19+481506.2 - A Partially Eclipsing AM CVn System Discovered in the Palomar Transient Factory

We report on PTF1 J191905.19+481506.2, a newly discovered, partially eclipsing, outbursting AM CVn system found in the Palomar Transient Factory synoptic survey. This is only the second known eclipsing AM CVn system. We use high-speed photometric observations and phase-resolved spectroscopy to establish an orbital period of 22.4559(3) min. We also present a long-term light curve and report on the normal and super-outbursts regularly seen in this system, including a super-outburst recurrence time of 36.8(4) d. We use the presence of the eclipse to place upper and lower limits on the inclination of the system and discuss the number of known eclipsing AM CVn systems versus what would be expected.

astro-ph.SR↗