Interplanetary Network Research Articles

GRB 180128A: A second magnetar giant flare candidate from the Sculptor Galaxy

Magnetars are slowly rotating neutron stars that possess the strongest magnetic fields known in the cosmos (1014 − 1015 G). They display a range of transient high-energy electromagnetic activity. The brightest and most energetic of these events are the gamma-ray bursts (GRBs) known as magnetar giant flares (MGFs), with isotropic energies Eiso ≈ 1044 − 1046 erg. Only seven MGF detections have been made to date: three unambiguous events occurred in our Galaxy and the Magellanic Clouds, and the other four MGF candidates are associated with nearby star-forming galaxies. As all seven identified MGFs are bright at Earth, additional weaker events likely remain unidentified in archival data. We conducted a search of the Fermi Gamma-ray Burst Monitor database for candidate extragalactic MGFs and, when possible, collected localization data from the Interplanetary Network (IPN) satellites. Our search yielded one convincing event, GRB 180128A. IPN localizes this burst within NGC 253, commonly known as the Sculptor Galaxy. The event is the second MGF in modern astronomy to be associated with this galaxy and the first time two bursts have been associated with a single galaxy outside our own. Here we detail the archival search criteria that uncovered this event and its spectral and temporal properties, which are consistent with expectations for a MGF. We also discuss the theoretical implications and finer burst structures resolved from various binning methods. Our analysis provides observational evidence of an eighth identified MGF.

Localization of cosmic gamma-ray bursts in interplanetary space with MGNS/BepiColombo and HEND/Mars Odyssey experiments

This paper describes the methods and results for the localization by triangulation of cosmic gamma-ray bursts (GRBs) independently observed by two space experiments: the Mercury Gamma-ray and Neutron Spectrometer (MGNS) and the High Energy Neutron Detector (HEND). MGNS is onboard the MPO/BepiColombo mission and on a stage of cruise to Mercury whereas HEND is onboard Mars Odyssey mission and in orbit around Mars. An analysis is performed of the accuracy of localization of the GRBs jointly observed by the two instruments at interplanetary distances by comparing their light curves. Notable achievements and scientific opportunities are described also in light of the recent inclusion of MGNS within the program of interplanetary network for gamma-ray burst localization (IPN). • A localization procedure by triangulation of cosmic gamma-ray bursts (GRBs) independently observed by two space experiments MGNS and HEND procedure was created. • Describes the methods and results for the localization procedure. • An analysis is performed of the accuracy of localization of the GRBs. A comparison was performed with the localization done by other experiments. • The first results of the MGNS experiment as part of program of interplanetary network (IPN) are described.

The Second Catalog of Interplanetary Network Localizations of Konus Short-duration Gamma-Ray Bursts

Abstract We present the catalog of InterPlanetary Network (IPN) localizations for 199 short-duration gamma-ray bursts (sGRBs) detected by the Konus-Wind (KW) experiment between 2011 January 1 and 2021 August 31, which extends the initial sample of IPN-localized KW sGRBs to 495 events. We present the most comprehensive IPN localization data on these events, including probability sky maps in Hierarchical Equal Area isoLatitude Pixelization format.

Nazgul: A statistical approach to gamma-ray burst localization

Context. Gamma-ray bursts (GRBs) can be located via arrival time signal triangulation using gamma-ray detectors in orbit throughout the solar system. The classical approach based on cross-correlations of binned light curves ignores the Poisson nature of the time series data, and it is unable to model the full complexity of the problem. Aims. We aim to present a statistically proper and robust GRB timing and triangulation algorithm as a modern update to the original procedures used for the interplanetary network. Methods. A hierarchical Bayesian forward model for the unknown temporal signal evolution is learned via random Fourier features and fitted to each detector’s time series data with time differences that correspond to the position GRBs on the sky via the appropriate Poisson likelihood. Results. Our novel method can robustly estimate the position of a GRB as verified via simulations. The uncertainties generated by the method are robust and in many cases more precise compared to the classical method. Thus, we have a method that can become a valuable tool for gravitational wave follow-up.

Discovery and confirmation of the shortest gamma-ray burst from a collapsar

Gamma-ray bursts (GRBs) are among the brightest and most energetic events in the universe. The duration and hardness distribution of GRBs has two clusters, now understood to reflect (at least) two different progenitors. Short-hard GRBs (SGRBs; T90 <2 s) arise from compact binary mergers, while long-soft GRBs (LGRBs; T90 >2 s) have been attributed to the collapse of peculiar massive stars (collapsars). The discovery of SN 1998bw/GRB 980425 marked the first association of a LGRB with a collapsar and AT 2017gfo/GRB 170817A/GW170817 marked the first association of a SGRB with a binary neutron star merger, producing also gravitational wave (GW). Here, we present the discovery of ZTF20abwysqy (AT2020scz), a fast-fading optical transient in the Fermi Satellite and the InterPlanetary Network (IPN) localization regions of GRB 200826A; X-ray and radio emission further confirm that this is the afterglow. Follow-up imaging (at rest-frame 16.5 days) reveals excess emission above the afterglow that cannot be explained as an underlying kilonova (KN), but is consistent with being the supernova (SN). Despite the GRB duration being short (rest-frame T90 of 0.65 s), our panchromatic follow-up data confirms a collapsar origin. GRB 200826A is the shortest LGRB found with an associated collapsar; it appears to sit on the brink between a successful and a failed collapsar. Our discovery is consistent with the hypothesis that most collapsars fail to produce ultra-relativistic jets.

Possible Periodic Windowed Behavior in SGR1935+2154 Bursts

It has been proposed that repeating fast radio burst (FRB) sources, FRB 20180916B and FRB 20121102A display periodic windowed behavior (PWB) in the times of FRB detections. In PWB, events occur only within a periodic activity window spanning a fixed fraction of the period, but no events might be detected during many periods. During UT 2020 April 28, two peaks of a soft gamma burst (detected with Insight-HXMT) were identified with two FRB peaks from soft gamma repeater (SGR) 1935+2154. As SGRs are a type of magnetar, a neutron star with an extremely high magnetic field, ∼1014 G, these observations establish a link between at least some FRBs and magnetars. The analysis herein shows possible PWB in SGR 1935+2154's soft gamma-ray burst times. For 161 bursts from 2014 through 2020 from IPN (Interplanetary Network) instruments, a resolved minimum in active window fraction versus period occurs at a 231 ± 9.3 day period, at a 55% active window fraction. The data cover only 6 bursting episodes, however, the periodicity result appears relatively robust: First, the IPN has excellent time coverage and is unlikely to miss bright bursts outside of active windows. Second, for various data subsets (with significantly less bursts), either the best or second best measured period was consistent with 231 days, even in the sub-sample with the richest bursting episode removed. In addition, simulations show that even small numbers of uniform random bursts do not show PWB, and that the results are not due to limited sampling. The appearance of PWB could have alternative explanations, including a non-uniform distribution of burst times; a firm conclusion of PWB would be evident, however, after the observation of more episodes consistent (within a small phase margin) with the given windows. If the periodicity of this SGR’s bursts can be verified, and if similar behavior were observed in other repeating FRB sources, it might suggest a linkage between FRB and SGR burst mechanisms or emission conditions.

MARS: A Multi-Attribute Routing and Scheduling Algorithm for DTN Interplanetary Networks

The Interplanetary Network (IPN) or the Interplanetary Internet is a network composed of interconnected space objects, which are in turn connected to mission control stations on the surface of Earth. The IPN is our only portal to the deep space, and yet it has been relatively sparse, until recently. With the ongoing and the planned missions to the outer space, the Delay Tolerant Networking (DTN) based network infrastructure will require more scalable routing and scheduling algorithms. In this paper, we propose the first Mixed Integer Linear Programming (MILP) model for message routing and scheduling in the IPN using Multi-Attribute Decision Making (MADM) principles. Based on this model, we propose a novel MADM-based algorithm called Multi-Attribute Routing and Scheduling (MARS) algorithm. This algorithm uses a sliding window of size $n$ to schedule the first $n$ messages in the buffer based on multiple attributes. After finding the optimal schedule for these messages (in terms of delivery rate), they are routed using our proposed Dijkstra-based routing algorithm. We use an existing MADM technique, PROMETHEE II, and consider the four main attributes of a message: size, priority, time to live (TTL), and time in buffer (TiB). Finally, we run multiple simulation experiments in order to test the performance of the proposed MARS and show that MADM coupled with scheduling and routing in IPN delivers at least three times more messages than a previously proposed technique, the Contact Graph Routing (CGR), while significantly reducing the average end-to-end delay and overhead.

A Decade of Gamma-Ray Bursts Observed by Fermi-LAT: The Second GRB Catalog

Abstract The Large Area Telescope (LAT) aboard the Fermi spacecraft routinely observes high-energy emission from gamma-ray bursts (GRBs). Here we present the second catalog of LAT-detected GRBs, covering the first 10 yr of operations, from 2008 to 2018 August 4. A total of 186 GRBs are found; of these, 91 show emission in the range 30–100 MeV (17 of which are seen only in this band) and 169 are detected above 100 MeV. Most of these sources were discovered by other instruments (Fermi/GBM, Swift/BAT, AGILE, INTEGRAL) or reported by the Interplanetary Network (IPN); the LAT has independently triggered on four GRBs. This catalog presents the results for all 186 GRBs. We study onset, duration, and temporal properties of each GRB, as well as spectral characteristics in the 100 MeV–100 GeV energy range. Particular attention is given to the photons with the highest energy. Compared with the first LAT GRB catalog, our rate of detection is significantly improved. The results generally confirm the main findings of the first catalog: the LAT primarily detects the brightest GBM bursts, and the high-energy emission shows delayed onset as well as longer duration. However, in this work we find delays exceeding 1 ks and several GRBs with durations over 10 ks. Furthermore, the larger number of LAT detections shows that these GRBs not only cover the high-fluence range of GBM-detected GRBs but also sample lower fluences. In addition, the greater number of detected GRBs with redshift estimates allows us to study their properties in both the observer and rest frames. Comparison of the observational results with theoretical predictions reveals that no model is currently able to explain all results, highlighting the role of LAT observations in driving theoretical models.

INO: Interplanetary network of optical lattice clocks

The new technique of measuring frequency by optical lattice clocks now approaches to the relative precision of [Formula: see text]. We propose to place such precise clocks in space and to use Doppler tracking method for detecting low-frequency gravitational wave below 1[Formula: see text]Hz. Our idea is to locate three spacecrafts at one A.U. distance (say at L1, L4 and L5 of the Sun–Earth orbit), and apply the Doppler tracking method by communicating “the time” each other. Applying the current available technologies, we obtain the sensitivity for gravitational wave with third- or fourth-order improvement ([Formula: see text] or [Formula: see text] level in [Formula: see text]–[Formula: see text][Formula: see text]Hz) than that of Cassini spacecraft in 2001. This sensitivity enables us to observe black hole (BH) mergers of their mass greater than [Formula: see text] in the cosmological scale. Based on the hierarchical growth model of BHs in galaxies, we estimate the event rate of detection will be 20–50 a year. We nickname “INO” (Interplanetary Network of Optical Lattice Clocks) for this system, named after Tadataka Ino (1745–1818), a Japanese astronomer, cartographer, and geodesist.

A Search for Gravitationally Lensed Gamma-Ray Bursts in the Data of the Interplanetary Network and Konus-Wind

Abstract We examine a sample of 2301 gamma-ray bursts, detected by Konus-Wind in the triggered mode between 1994 and 2017 and localized by the interplanetary network (IPN), for evidence of gravitational lensing. We utilize all the available gamma-ray burst (GRB) data: time histories, localizations, and energy spectra. We employ common IPN techniques to find and quantify similarities in the light curves of 2,646,150 burst pairs, and for the pairs with significant similarities, we examine their IPN localizations to determine whether they are consistent with a common origin. For pairs that are consistent, we derive and compare energy spectra, and compute a figure of merit that allows us to compare and rank burst pairs. We conduct both a blind search, between all possible burst pairs, and a targeted search, between pairs in which one burst has both a spectroscopic redshift and an identification of an intervening system, as measured by one or more lower spectroscopic redshifts. We identify six pairs in the blind search that could be taken as evidence for lensing, but none are compelling enough to claim a detection with good confidence. No candidates were detected in the targeted search. For our GRB sample, we set an upper limit to the optical depth to lensing of 0.0033, which is comparable to that of optical sources. We conclude that proposed scenarios in which a large fraction of the GRB population is lensed are extremely unlikely.

Modeling Space-Terrestrial Integrated Networks with Smart Collaborative Theory

Driven by the requirements of space exploration and terrestrial investigation, interplanetary network merging has been widely focused on by academia, industry, and the military. Although system architecture and layered workflow are updated endlessly, the pervasive methodology is still urgently needed to provide a unified solution for heterogeneous elements. In this article, we propose a modeling scheme named generalized logical sphere (GLS) for space-terrestrial networks based on smart collaborative theory. First, the coverage range, transmission mechanism, and practice guideline of integration evolution are fully analyzed via three phases to guarantee the comprehensive combinations. Then the specific approach as well as the advanced characteristics of GLS (i.e., load balancing, smart routing, cognitive healing, and hierarchical shielding) are presented and discussed. Finally, a prototype platform is established to validate the correctness. The results of two scenarios illustrate the functionality and practicability of our model.

GLADE: A galaxy catalogue for multimessenger searches in the advanced gravitational-wave detector era

We introduce a value-added full-sky catalogue of galaxies, named as Galaxy List for the Advanced Detector Era, or GLADE. The purpose of this catalogue is to (i) help identifications of host candidates for gravitational-wave events, (ii) support target selections for electromagnetic follow-up observations of gravitational-wave candidates, (iii) provide input data on the matter distribution of the local universe for astrophysical or cosmological simulations, and (iv) help identifications of host candidates for poorly localised electromagnetic transients, such as gamma-ray bursts observed with the InterPlanetary Network. Both being potential hosts of astrophysical sources of gravitational waves, GLADE includes inactive and active galaxies as well. GLADE was constructed by cross-matching and combining data from five separate (but not independent) astronomical catalogues: GWGC, 2MPZ, 2MASS XSC, HyperLEDA and SDSS-DR12Q. GLADE is complete up to $d_L = 37^{+3}_{-4}$ Mpc in terms of the cumulative B-band luminosity of galaxies within luminosity distance $d_L$, and contains all of the brightest galaxies giving half of the total B-band luminosity up to $d_L = 91$ Mpc. As B-band luminosity is expected to be a tracer of binary neutron star mergers (currently the prime targets of joint GW+EM detections), our completeness measures can be used as estimations of completeness for containing all binary neutron star merger hosts in the local universe.

An Interplanetary Network for Spacecraft Autonomous Navigation

An interplanetary autonomous navigation network, named the Internet of Spacecraft (IoS), is proposed in this paper to enable a Solar System-wide autonomous navigation capability for spacecraft. This network consists of two types of spacecraft, namely host and client spacecraft. The former provide the absolute reference for the whole network, and the latter determine their positions by communicating with the host spacecraft or other client spacecraft. To investigate the performance of IoS, a detailed application scheme that supports a flight from Earth to Mars is developed and analysed. IoS is not a simple extension of the navigation constellation. It is independent of the ground tracking system and the configuration of the network is flexible in that any spacecraft-installed identical device can be added to it. Moreover, client spacecraft whose positions have been determined can also be regarded as host spacecraft and provide further navigation information to others. This paper aims to provide technical support for future deep space exploration.

Search for Gravitational Waves Associated with Gamma-Ray Bursts during the First Advanced LIGO Observing Run and Implications for the Origin of GRB 150906B

Abstract We present the results of the search for gravitational waves (GWs) associated with γ-ray bursts detected during the first observing run of the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO). We find no evidence of a GW signal for any of the 41 γ-ray bursts for which LIGO data are available with sufficient duration. For all γ-ray bursts, we place lower bounds on the distance to the source using the optimistic assumption that GWs with an energy of were emitted within the – Hz band, and we find a median 90% confidence limit of 71 Mpc at 150 Hz. For the subset of 19 short/hard γ-ray bursts, we place lower bounds on distance with a median 90% confidence limit of 90 Mpc for binary neutron star (BNS) coalescences, and 150 and 139 Mpc for neutron star–black hole coalescences with spins aligned to the orbital angular momentum and in a generic configuration, respectively. These are the highest distance limits ever achieved by GW searches. We also discuss in detail the results of the search for GWs associated with GRB 150906B, an event that was localized by the InterPlanetary Network near the local galaxy NGC 3313, which is at a luminosity distance of Mpc (z = 0.0124). Assuming the γ-ray emission is beamed with a jet half-opening angle , we exclude a BNS and a neutron star–black hole in NGC 3313 as the progenitor of this event with confidence &gt;99%. Further, we exclude such progenitors up to a distance of 102 Mpc and 170 Mpc, respectively.

The InterPlanetary Network Supplement to the Second Fermi GBM Catalog of Cosmic Gamma-Ray Bursts

Abstract InterPlanetary Network (IPN) data are presented for the gamma-ray bursts in the second Fermi Gamma-Ray Burst Monitor (GBM) catalog. Of the 462 bursts in that catalog between 2010 July 12 and 2012 July 11, 428, or 93%, were observed by at least 1 other instrument in the 9-spacecraft IPN. Of the 428, the localizations of 165 could be improved by triangulation. For these bursts, triangulation gives one or more annuli whose half-widths vary between about 2.′3° and 16°, depending on the peak flux, fluence, time history, arrival direction, and the distance between the spacecraft. We compare the IPN localizations with the GBM 1σ, 2σ, and 3σ error contours and find good agreement between them. The IPN 3σ error boxes have areas between about 8 square arcminutes and 380 square degrees, and are an average of 2500 times smaller than the corresponding GBM 3σ localizations. We identify four bursts in the IPN/GBM sample whose origins were given as “uncertain,” but may in fact be cosmic. This leads to an estimate of over 99% completeness for the GBM catalog.

A Large Catalog of Homogeneous Ultra-Violet/Optical GRB Afterglows: Temporal and Spectral Evolution

Abstract We present the second Swift Ultra-Violet/Optical Telescope (UVOT) gamma-ray burst (GRB) afterglow catalog, greatly expanding on the first Swift UVOT GRB afterglow catalog. The second catalog is constructed from a database containing over 120,000 independent UVOT observations of 538 GRBs first detected by Swift, the High Energy Transient Explorer 2 (HETE2), the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL), the Interplanetary Network (IPN), Fermi, and Astro-rivelatore Gamma a Immagini Leggero (AGILE). The catalog covers GRBs discovered from 2005 January 17 to 2010 December 25. Using photometric information in three UV bands, three optical bands, and a “white” or open filter, the data are optimally coadded to maximize the number of detections and normalized to one band to provide a detailed light curve. The catalog provides positional, temporal, and photometric information for each burst, as well as Swift Burst Alert Telescope and X-ray Telescope (XRT) GRB parameters. Temporal slopes are provided for each UVOT filter. The temporal slope per filter of almost half the GRBs are fit with a single power law, but one to three breaks are required in the remaining bursts. Morphological comparisons with the X-ray reveal that of the UVOT light curves are similar to one of the four morphologies identified by Evans et al. (2009). The remaining have a newly identified morphology. For many bursts, redshift- and extinction-corrected UV/optical spectral slopes are also provided at 2 × 103, 2 × 104, and 2 × 105 s.

First intermediate flare from SGR 1935+2154

The first intermediate flare from newly discovered SGR 1935+2154 was detected and localized by four Interplanetary network (IPN) spacecraft on 2015 April 12. Among the observing instruments, only Konus- Wind gamma-ray burst spectrometer (KW) was able to measure high-resolution light curves and multi-channel energy spectra of the flare. We report on the results of temporal and spectral analyses of the KW data, the flare energetics, a search for Quasi-Periodic Oscillations in the light curve, and, finally, discuss the source distance estimate based on the distribution of double blackbody spectral fit parameters

THE INTERPLANETARY NETWORK RESPONSE TO LIGO GW150914

ABSTRACT We have performed a blind search for a gamma-ray transient of arbitrary duration and energy spectrum around the time of the LIGO gravitational-wave event GW150914 with the six-spacecraft interplanetary network (IPN). Four gamma-ray bursts were detected between 30 hr prior to the event and 6.1 hr after it, but none could convincingly be associated with GW150914. No other transients were detected down to limiting 15–150 keV fluences of roughly 5 ×10−8–5 × 10−7 erg cm−2. We discuss the search strategies and temporal coverage of the IPN on the day of the event and compare the spatial coverage to the region where GW150914 originated. We also report the negative result of a targeted search for the Fermi-GBM event reported in conjunction with GW150914.

INVESTIGATION OF PRIMORDIAL BLACK HOLE BURSTS USING INTERPLANETARY NETWORK GAMMA-RAY BURSTS

ABSTRACT The detection of a gamma-ray burst (GRB) in the solar neighborhood would have very important implications for GRB phenomenology. The leading theories for cosmological GRBs would not be able to explain such events. The final bursts of evaporating primordial black holes (PBHs), however, would be a natural explanation for local GRBs. We present a novel technique that can constrain the distance to GRBs using detections from widely separated, non-imaging spacecraft. This method can determine the actual distance to the burst if it is local. We applied this method to constrain distances to a sample of 36 short-duration GRBs detected by the Interplanetary Network (IPN) that show observational properties that are expected from PBH evaporations. These bursts have minimum possible distances in the 1013–1018 cm (7–105 au) range, which are consistent with the expected PBH energetics and with a possible origin in the solar neighborhood, although none of the bursts can be unambiguously demonstrated to be local. Assuming that these bursts are real PBH events, we estimate lower limits on the PBH burst evaporation rate in the solar neighborhood.

The first observation of an intermediate flare from SGR 1935+2154

We report on the bright burst detected by four Interplanetary network (IPN) spacecraft on 2015 April 12. The IPN localization of the source is consistent with the position of the recently discovered soft gamma-repeater SGR 1935+2154. From the Konus-Wind (KW) observation, we derive temporal and spectral parameters of the emission, and the burst energetics. The rather long duration of the burst ($\sim$1.7 s) and the large measured energy fluence ($\sim2.5\times10^{-5}$ erg cm$^{-2}$) put it in the class of rare "intermediate" SGR flares, and this is the first one observed from SGR 1935+2154. A search for quasi-periodic oscillations in the KW light curve yields no statistically significant signal. Of four spectral models tested, optically thin thermal bremsstrahlung and a single blackbody (BB) function can be rejected on statistical grounds; two more complex models, a cutoff power law (CPL) and a sum of two BB functions (2BB), fit the burst spectra well and neither of them may be ruled out by the KW observation. The CPL and 2BB model parameters we report for this bright flare are typical of SGRs; they are also consistent with those obtained from observations of much weaker and shorter SGR 1935+2154 bursts with other instruments. From the distribution of double blackbody spectral fit parameters we estimate the SGR 1935+2154 distance to be $<$10.0 kpc, in agreement with that of the Galactic supernova remnant G57.2+0.8 at 9.1 kpc.