High Galactic Latitude Research Articles

Revisiting the Vertical Distribution of H i Absorbing Clouds in the Solar Neighborhood. II. Constraints from a Large Catalog of 21 cm Absorption Observations at High Galactic Latitudes

The cold neutral medium (CNM) is where neutral atomic hydrogen (H i) is converted into molecular clouds, so the structure and kinematics of the CNM are key drivers of galaxy evolution. Here we provide new constraints on the vertical distribution of the CNM using the recently developed kinematic_scaleheight software package and a large catalog of sensitive H i absorption observations. We estimate the thickness of the CNM in the solar neighborhood to be σ z ∼ 50–90 pc, assuming a Gaussian vertical distribution. This is a factor of ∼2 smaller than typically assumed, indicating that the thickness of the CNM in the solar neighborhood is similar to that found in the inner Galaxy, consistent with recent simulation results. If we consider only structures with H i optical depths τ > 0.1 or column densities N(H i) > 1019.5 cm−2, which recent work suggests are thresholds for molecule formation, we find σ z ∼ 50 pc. Meanwhile, for structures with τ < 0.1 or column densities N(H i) < 1019.5 cm−2, we find σ z ∼ 120 pc. These thicknesses are similar to those derived for the thin- and thick-disk molecular cloud populations traced by CO emission, possibly suggesting that cold H i and CO are well mixed. Approximately 20% of CNM structures are identified as outliers, with kinematics that are not well explained by Galactic rotation. We show that some of these CNM structures—perhaps representing intermediate-velocity clouds—are associated with the Local Bubble wall. We compare our results to recent observations and simulations, and we discuss their implications for the multiphase structure of the Milky Way’s interstellar medium.

Quantifying interstellar extinction at high galactic latitudes

Abstract A detailed map of the distribution of dust at high Galactic latitudes is essential for future cosmic microwave background (CMB) polarization experiments because the dust, while diffuse, remains a significant foreground in these regions. We develop a Bayesian model to identify a region of the Hertzsprung-Russell (HR) diagram suited to constrain the single-star extinction accurately at high Galactic latitudes. Using photometry from Gaia, 2MASS and ALLWISE, and parallax from Gaia, we employ nested sampling to fit the model to the data and analyse the posterior over stellar parameters for both synthetic and real data. Charting low variations in extinction is complex due to systematic errors and degeneracies between extinction and other stellar parameters. The systematic errors can be minimised by restricting our data to a region of the HR diagram where the stellar models are most accurate. Moreover, the degeneracies can be reduced by including astrophysical priors and spectroscopic constraints. We show that accounting for the measurement error of the data and the assumed inaccuracies of the stellar models are critical in accurately recovering small variations in extinction. We compare the posterior distribution for individual stars with spectroscopic stellar parameter estimates from LAMOST and Gaia ESO and illustrate the importance of estimating extinction and effective temperature as a joint solution.

Identification and Distance Measurement of Dust Clouds at High Latitude by a Clustering Hierarchical Algorithm

We present a catalog of dust clouds at high Galactic latitude based on the Planck 857 GHz dust emission data. Using a clustering hierarchical algorithm, 315 dust clouds at high Galactic latitudes are identified. Additionally, using the optical and ultraviolet extinction of 4 million and 1 million stars, respectively, provided by Sun et al., we derive the distances and physical properties for 190 high Galactic latitude dust clouds and the ultraviolet excess ratios for 165 of them. Through the study of color excess ratios, this work confirms that molecular clouds with large Galactic distances and low extinction likely have a higher proportion of small-sized dust grains. In addition, clouds with well-defined distances in the catalog are used to trace the Local Bubble, showing good consistency with the boundary of the Local Bubble from the literature.

Local H i absorption towards the magellanic cloud foreground using ASKAP

ABSTRACT We present the largest Galactic neutral hydrogen H i absorption survey to date, utilizing the Australian SKA Pathfinder Telescope at an unprecedented spatial resolution of 30 arcsec. This survey, GASKAP-H i, unbiasedly targets 2714 continuum background sources over 250 square degrees in the direction of the Magellanic Clouds, a significant increase compared to a total of 373 sources observed by previous Galactic absorption surveys across the entire Milky Way. We aim to investigate the physical properties of cold (CNM) and warm (WNM) neutral atomic gas in the Milky Way foreground, characterized by two prominent filaments at high Galactic latitudes (between $-45^{\circ }$ and $-25^{\circ }$). We detected strong H i absorption along 462 lines of sight above the 3$\sigma$ threshold, achieving an absorption detection rate of 17 per cent. GASKAP-H i’s unprecedented angular resolution allows for simultaneous absorption and emission measurements to sample almost the same gas clouds along a line of sight. A joint Gaussian decomposition is then applied to absorption-emission spectra to provide direct estimates of H i optical depths, temperatures, and column densities for the CNM and WNM components. The thermal properties of CNM components are consistent with those previously observed along a wide range of Solar neighbourhood environments, indicating that cold H i properties are widely prevalent throughout the local interstellar medium. Across our region of interest, CNM accounts for $\sim$30 per cent of the total H i gas, with the CNM fraction increasing with column density towards the two filaments. Our analysis reveals an anticorrelation between CNM temperature and its optical depth, which implies that CNM with lower optical depth leads to a higher temperature.

The SRG/eROSITA diffuse soft X-ray background

Context. The SRG/eROSITA All-Sky Surveys (eRASSs) combine the advantages of complete sky coverage and the energy resolution provided by the charge couple device and offer the most holistic and detailed view of the diffuse soft X-ray background (SXRB) to date. The first eRASS (eRASSl) was completed at solar minimum, when solar wind charge exchange emission was minimal, providing the clearest view of the SXRB. Aims. We aim to extract spatial and spectral information from each constituent of the SXRB in the western Galactic hemisphere, focusing on the local hot bubble (LHB). Methods. We extracted and analysed eRASSl spectra from almost all directions in the western Galactic hemisphere by dividing the sky into equal signal-to-noise bins. We fitted all bins with fixed spectral templates of known background constituents. Results. We find the temperature of the LHB exhibits a north-south dichotomy at high latitudes (|b| &gt; 30°), with the south being hotter, with a mean temperature at kT = 121.8 ± 0.6 eV and the north at kT = 100.8 ± 0.5 eV. At low latitudes, the LHB temperature increases towards the Galactic plane, especially towards the inner Galaxy. The LHB emission measure (EMLHB) enhances approximately towards the Galactic poles. The EMLHB map shows clear anti-correlation with the local dust column density. In particular, we found tunnels of dust cavities filled with hot plasma, potentially forming a wider network of hot interstellar medium. We also constructed a three-dimensional LHB model from EMLHB, assuming constant density. The average thermal pressure of the LHB is Pthermal/k = 10100−1500+1200 cm−3 K, a lower value than typical supernova remnants and wind-blown bubbles. This could be an indication of the LHB being open towards high Galactic latitudes.

H i Kinematics and the E(B − V)/N(H i) Ratio

The λ21 cm H i emission that is used to trace the gas-to-dust ratio at high Galactic latitudes has contributions from material beyond the Milky Way disk, with uncertain and likely subsolar metallicity and dust content. These contributions can be isolated kinematically and their presence is clear for sightlines with small mean reddening 〈E(B − V)〉 ≲ 0.03 mag, which have mean ratios 〈N(H i)〉/〈E(B − V)〉 that are 20%–50% above the high-latitude Galactic average 〈N(H i)〉/〈E(B − V)〉 = 8.3 × 1021 cm−2 mag−1. By mapping N(H i) and E(B − V) across H i high-velocity cloud complexes and the Magellanic Clouds, we show that the reddening of this kinematically isolated gas is on average 5 times smaller per H i than the high-latitude average. However, the aggregate contribution of this gas is small and 〈N(H i)〉/〈E(B − V)〉 = 8.3 × 1021 cm−2 mag−1 is the appropriate value for Galactic gas seen at high latitude using the H i and reddening measures employed here and in our previous work.

Host Galaxies for Four Nearby CHIME/FRB Sources and the Local Universe FRB Host Galaxy Population

We present the host galaxies of four apparently nonrepeating fast radio bursts (FRBs), FRB 20181223C, FRB 20190418A, FRB 20191220A, and FRB 20190425A, reported in the first Canadian Hydrogen Intensity Mapping Experiment (CHIME/FRB) catalog. Our selection of these FRBs is based on a planned hypothesis testing framework where we search all CHIME/FRB Catalog-1 events that have low extragalactic dispersion measure (<100 pc cm−3), with high Galactic latitude (∣b∣ > 10°) and saved baseband data. We associate the selected FRBs with galaxies with moderate to high star formation rates located at redshifts between 0.027 and 0.071. We also search for possible multimessenger counterparts, including persistent compact radio and gravitational-wave sources, and find none. Utilizing the four FRB hosts from this study, along with the hosts of 14 published local Universe FRBs (z < 0.1) with robust host association, we conduct an FRB host demographics analysis. We find all 18 local Universe FRB hosts in our sample to be spirals (or late-type galaxies), including the host of FRB 20220509G, which was previously reported to be elliptical. Using this observation, we scrutinize proposed FRB source formation channels and argue that core-collapse supernovae are likely the dominant channel to form FRB sources. Moreover, we infer no significant difference in the host properties of repeating and apparently nonrepeating FRBs in our local Universe FRB host sample. Finally, we find the burst rates of these four apparently nonrepeating FRBs to be consistent with those of the sample of localized repeating FRBs observed by CHIME/FRB. Therefore, we encourage further monitoring of these FRBs with more sensitive radio telescopes.

The Fourth S-PLUS Data Release: 12-filter photometry covering ~3000 square degrees in the southern hemisphere

The Southern Photometric Local Universe Survey (S-PLUS) is a project to map $ sq deg of the sky using twelve bands (seven narrow and five broadbands). Observations are performed with the T80-South telescope, a robotic telescope located at the Cerro Tololo Observatory in Chile. The survey footprint consists of several large contiguous areas, including fields at high and low galactic latitudes, and towards the Magellanic Clouds. S-PLUS uses fixed exposure times to reach point source depths of about $21$ mag in the $griz$ and $20$ mag in the $u$ and the narrow filters. This paper describes the S-PLUS Data Release 4 (DR4), which includes calibrated images and derived catalogues for over 3000 sq deg, covering the aforementioned area. The catalogues provide multi-band photometry performed with the tools DoPHOT and SExtractor -- point spread function ( and aperture photometry, respectively. In addition to the characterization, we also present the scientific potential of the data. We use statistical tools to present and compare the photometry obtained through different methods. Overall we find good agreement between the different methods, with a slight systematic offset of 0.05\,mag between our and aperture photometry. We show that the astrometry accuracy is equivalent to that obtained in previous S-PLUS data releases, even in very crowded fields where photometric extraction is challenging. The depths of main survey (MS) photometry for a minimum signal-to-noise ratio $S/N = 3$ reach from $ for the bluer bands to $ mag on the red. The range of magnitudes over which accurate photometry is obtained is shallower, reaching $ to $ mag depending on the filter. Based on these photometric data, we provide star-galaxy-quasar classification and photometric redshift for millions of objects. We demonstrate the versatility of the data by presenting the results of a project to identify members of four Abell galaxy clusters in the Local Universe. The S-PLUS DR4 data allow for a reliable assessment of cluster membership out to a large radius corresponding to $5 $. The S-PLUS DR4 can be accessed through the survey data portal. All the software used to generate the catalogues for this release and the scientific investigation presented is available in the collaboration GitHub repository. The S-PLUS DR4 consists of a large, calibrated public dataset, providing powerful ways for studying Galactic and extra-galactic objects through an extensive set of (broad and narrow) filters.

The digitized First Byurakan Survey database. New carbon stars confirmed

Some amount of the new carbon ( C ) stars was confirmed among the sample of the Late-Type Stars (LTSs) candidates, selected on the Digitized First Byurakan Survey (DFBS) spectral plates. The DFBS is the digitized version of the First Byurakan Survey (FBS, or Markarian survey). The FBS was the first systematic survey of the extragalactic sky. This objective-prism survey was carried out in 1965- 1980 by B. E. Markarian and colleagues using the 1 m Schmidt telescope of the Byurakan Astrophysical Observatory. In this work we present Gaia DR3 photometric data, spectra, light curves, distances, high above/below Galactic plane, radial velocities (RV), and other important physical characteristics from modern astronomical catalogues for some amount new confirmed DFBS carbon stars. The confirmation is based on Gaia DR3 BP/RP low-resolution spectral database. In previous studies of the DFBS plates, these objects were presented as LTSs candidates. Some objects are located more than 7 kpc from the Galactic plane. Four of them are N-type C stars, from which two are Mira-type variables. The remaining objects are CH-type giants at high Galactic latitudes. Most probably they present binary systems.

The Digitized First Byurakan Survey Database. Late-type stars candidates. New confirmations

More than 3000 Late-Type Stars (LTS) candidates was confirmed among the sample, selected on the Digitized First Byurakan Survey (DFBS) spectral plates. The DFBS is the digitized version of the First Byurakan Survey (FBS, or Markarian survey). This objective-prism survey was carried out in 1965- 1980 by B. E. Markarian and colleagues using the 1 m Schmidt telescope of the Byurakan Astrophysical Observatory (BAO). FBS spectral plates have been used long period to search and study faint LTS (Ctype (carbon) and M-type) stars at high Galactic latitudes. Thousands of objects was confirmed as LTS. The confirmation is based on Gaia DR3 BP/RP low-resolution spectral database. In previous studies of the DFBS plates, these objects were presented as LTS candidates. Some objects are located more than 10 kpc. The predominant part of the new confirmed objects are M dwarfs.

“Forbidden” stars in the eROSITA all-sky survey: X-ray emission from very late-type giants

We present the results of the first X-ray all-sky survey (eRASS1) performed by the eROSITA instrument aboard the Spectrum-Roentgen-Gamma (SRG) mission on X-ray emitting red giants and supergiants. Focusing on stars positioned at high galactic latitudes above 20°, we constructed a complete sample of such objects using the Gaia DR3 catalog and identified a sample 96 stars that appear as bona fide entries in the eRASS1 source catalog. By again restricting the sample to objects nearer than 1300 pc and eliminating all catalog entries that are due to optical contamination, we ended up with a sample of 16 genuine red giant or supergiant X-ray sources, most of which represent new X-ray detections. We present a low signal-to-noise X-ray spectrum of the nearby low-activity giant Arcturus obtained from a pointed observation with the XMM-Newton satellite and give a detailed account of our data analysis. We show that Arcturus-like X-ray emission cannot be the explanation for the X-ray emissions observed by eROSITA and provide a discussion of the possible nature of the detected X-ray sources.

Galactic Cirri at High Galactic Latitudes. I. Investigating Scatter in Slopes between Optical and Far-infrared Intensities

Based on the slopes between DESI g, r and Infrared Astronomical Satellite (IRAS) 100 μm intensities, specifically k g and k r , we have constructed a substantial sample of Galactic cirri. This sample covers 561.25 deg2 at high Galactic latitudes (∣b∣ ≥ 30°), allowing for a systematic study of the physical parameters of the Galactic cirrus on a large scale, such as g − r color, dust temperature, asymmetry factor, and albedo. The ratio of k g and k r is consistent with the diffuse Galactic starlight model, suggesting that the diffuse starlight within our own Galaxy serves as the primary illumination source for the cirrus. Both k g and k r decrease slowly with increasing Galactic latitudes and IRAS 100 μm intensities, while they do not have a correlation with Galactic longitudes. The distribution of k g and k r confirms a significant scatter in the slopes, reaching a factor of 4–5. Such large scatter cannot be explained by the weak correlation between the slopes and Galactic latitudes and IRAS 100 μm intensities. Instead, it is attributed to substantial variations in the intrinsic properties of the dust, e.g., asymmetry factor and albedo. We propose that the properties of dust particles play a critical role in the observed scatter in slopes, making them the primary contributing factors. Moreover, the variations in dust properties within the cirrus are localized rather than exhibiting large-scale gradients.

Analysis of Gaia DR3 Data of Selected High Galactic Latitude Hα Emission Stars

Gaia DR3 data of 52 high galactic latitude Hα emission stars selected from the paper of Stephenson are analyzed. Ten new variable stars and eight new high velocity stars have been found. Details of six post-AGB stars and several other interesting stars are discussed. Many of the stars presented in this paper have Gaia DR3 light curves and spectra. A detailed study of these 52 stars is needed to derive their chemical composition and to further understand their binarity, circumstellar matter and evolutionary status. The astrophysical parameters from the Gaia DR3 data reveal several hot (OBA) and several F and G-type stars in this sample. Some of them are metal-poor stars.

Associating LOFAR Galactic Faraday structures with the warm neutral medium

Faraday tomography observations with the Low Frequency Array (LOFAR) have unveiled a remarkable network of structures in polarized synchrotron emission at high Galactic latitudes. The observed correlation between LOFAR structures, dust polarization, and HI emission suggests a connection to the neutral interstellar medium (ISM). We investigated this relationship by estimating the rotation measure (RM) of the warm neutral (partially ionized) medium (WNM) in the local ISM. Our work combines UV spectroscopy from FUSE and dust polarization observations from Planck with LOFAR data. We derived electron column densities from UV absorption spectra toward nine background stars, within the field of published data from the LOFAR two-meter sky survey. The associated RMs were estimated using a local magnetic field model fitted to the dust polarization data of Planck. A comparison with Faraday spectra at the position of the stars suggests that LOFAR structures delineate a slab of magnetized WNM and synchrotron emission, located ahead of the bulk of the warm ionized medium. This conclusion establishes an astrophysical framework for exploring the link between Faraday structures and the dynamics of the magnetized multiphase ISM. It will be possible to test it on a larger sample of stars when maps from the full northern sky survey of LOFAR become available.

Kinematical and ellipsoidal properties of the inner-halo hot subdwarfs observed in Gaia DR3 and LAMOST DR7

Here, we report the kinematical parameters of inner-halo hot subdwarfs located within (d≤15kpc) at high Galactic latitudes (bo≥20). The study included three program stars for one of the extreme He-rich groups (eHe-1) with eccentricity (e= 0.65) and the z-component of the angular momentum (Jz = 4288.66 kpc km s−1), the inner halo program I with 121 points (Teff≥24,000) and their subsections, i.e. inner halo program II (sdB; 79 points) with (40,000≥Teff≥24,000) and inner halo program III (sdO; 42 points) with (80,000≥Teff≥40,000). First, we calculated the spatial velocities (U¯,V¯,W¯;kms−1) along the Galactic coordinates (i.e., 25.73 ± ± 5.07, 28.79 ± 5.37, −14.51 ± 3.81) and their dispersion velocities (σ1,σ2,σ3;kms−1) = (161.94 ± 12.73, 140.31 ± 11.85, 101.57 ± 10.08) and subsequently their subsections sdB and sdO. Second, we calculated the vertex longitudes (l2) and the Solar motion (S⊙=41.246.42kms−1) as well as their subsections. Finally, based on the kinematic relation of the ratio (σ2/σ1) and our previously computed numerical value of the angular rotation rate (|A−B|=26.07±5.10;kms−1kpc−1), we obtained the average Oort's constants as (A&B;kms−1kpc−1) = (9.38 ± 0.33, −16.69 ± 0.25).

Wideband polarization and spectral properties of 18 high Galactic latitude pulsars

The broad-spectrum polarization and spectral characteristics of pulsars contain crucial information about the origin of their radio emission. These properties, together with pulsar flux density variations, can also be used to guide future surveys of radio pulsars and probe the Galactic interstellar medium. In this paper, we present studies of 18 pulsars at high Galactic latitudes using the Ultra-Wideband Low (UWL) receiver of the Parkes radio telescope. For these pulsars, we measured their wideband flux densities, spectral indices, and polarization fractions. We obtain seven new rotation measures (RMs) and refine the RMs of another ten pulsars. In this sample of pulsars, we observed significant variations in their flux densities, suggesting that previous shallow surveys were likely to miss a population of pulsars at high galactic latitude. In addition, we identified a previously reported isolated pulsar (PSR J1947−18) as a potential binary system.

Systematic Search for and Study of Short-timescale Flare Structures in BL Lac Object Gamma-Ray Emission

We present here the first systematic search of short-timescale γ-ray flares from 29 high Galactic latitude BL Lac objects over 14 yr of Fermi Large Area Telescope data. Using a combined Bayesian Blocks and HOP algorithm, we identified seven high-quality orbital timescale flare segments from three sources and quantified 24 short-timescale flare structures. We then performed a comprehensive analysis of flare symmetry, power spectral density (PSD) of variability, and flux–photon index relation. The main results are as follows. (1) The flare symmetry parameter A shows a “U-shaped” distribution. Short-timescale flares are symmetric while long-timescale flares are asymmetric. The number of fast-rise, slow-decay and slow-rise, fast-decay type flares are equal. No correlation is found between A and peak/integral flux. No parameter evolution is seen between consecutive flares, either. The observations support a scenario where longer-timescale flares originate from the superposition of short, symmetric subhour flares. (2) PSD from yearly to hourly timescales is modeled using the CARMA process. At lower frequencies, the PSD follows the typical broken power-law form. The high-frequency region of the PSD exhibits a continuous power-law shape, indicating that γ-ray variability originates from a single physical process across all probed timescales. (3) The flux–photon index distribution shows a pattern of “harder-when-brighter” or “softer-when-brighter,” but becomes flat above a certain critical flux, with Γ ≈ 2. This behavior cannot be simply explained by a two-component or blazar sequence model, and we speculate it may be related to complex interplay between electron acceleration and cooling.

A 350 MHz Green Bank Telescope Survey of Unassociated Fermi LAT Sources: Discovery and Timing of 10 Millisecond Pulsars

We have searched for radio pulsations toward 49 Fermi Large Area Telescope (LAT) 1FGL Catalog γ-ray sources using the Green Bank Telescope at 350 MHz. We detected 18 millisecond pulsars (MSPs) in blind searches of the data; 10 of these were discoveries unique to our survey. 16 are binaries, with eight having short orbital periods P B < 1 day. No radio pulsations from young pulsars were detected, although three targets are coincident with apparently radio-quiet γ-ray pulsars discovered in LAT data. Here, we give an overview of the survey and present radio and γ-ray timing results for the 10 MSPs discovered. These include the only isolated MSP discovered in our survey and six short-P B binary MSPs. Of these, three have very-low-mass companions (M c ≪ 0.1 M ⊙) and hence belong to the class of black widow pulsars. Two have more massive, nondegenerate companions with extensive radio eclipses and orbitally modulated X-ray emission consistent with the redback class. Significant γ-ray pulsations have been detected from nine of the discoveries. This survey and similar efforts suggest that the majority of Galactic γ-ray sources at high Galactic latitudes are either MSPs or relatively nearby nonrecycled pulsars, with the latter having on average a much smaller radio/γ-ray beaming ratio as compared to MSPs. It also confirms that past surveys suffered from an observational bias against finding short-P B MSP systems.

Forty Hypervelocity Stars from Gaia DR3

Forty hypervelocity stars (HVS) are detected from a search for HVS in Gaia DR3 data whose G magnitudes are less than 17.0 and radial velocities are more +400 km s−1. The Gaia DR3 astrophysical parameters and spectra indicate that most of the HVS reported in this study are F, G, and K type metal-poor stars. Eleven stars are at high galactic latitudes. Included in this study are the B components of six nearby visual double stars BD-6 885B, HD 47503B, HD 53229B, HD 95123B, HD 180683B, and HD 202276B which are found to be HVS. The A components of these six visual doubles are less massive late-type stars with normal radial velocities. The source of hypervelocity of the B components is not clear. They may have less luminous and relatively massive degenerate component stars which are not yet detected. Further study of all these HVS is needed.

Gamma-ray detection of newly discovered Ancora supernova remnant: G288.8–6.3

Context. The supernova remnant (SNR) G288.8–6.3 was recently discovered as a faint radio shell at high Galactic latitude using observations with the Australian Square Kilometre Array Pathfinder (ASKAP) in the Evolutionary Map of the Universe (EMU) survey. Aims. We performed the first detailed investigation of the γ-ray emission from the G288.8–6.3 region, aiming to characterise the high-energy emission in the GeV regime from the newly discovered SNR, dubbed Ancora. Methods. Fifteen years of Fermi-Large Area Telescope (LAT) data were analysed at energies between 400 MeV and 1 TeV, and the excess seen in the region was modelled using different spatial and spectral models. Results. We detect spatially extended γ-ray emission coinciding with the radio SNR, with detection significance up to 8.8 σ. A radial disk spatial model in combination with a power-law spectral model with an energy flux of (4.80 ± 0.91) × 10−6 MeV cm−2 s−1, with the spectrum extending up to around 5 GeV was found to be the preferred model. Morphologically, hotspots seen above 1 GeV are well correlated with the bright western part of the radio shell. The emission is more likely to be of leptonic origin, given the estimated gas density in the region and the estimated distance and age of the SNR, but a hadronic scenario cannot be ruled out. Conclusions. Ancora is the seventh confirmed SNR detected at high Galactic latitude with Fermi-LAT. The study of this new population of remnants can provide insights into the evolutionary aspects of SNRs and their properties, and further advance efforts of constraining the physics of particle diffusion and escape from SNRs into the Galaxy.