astro-legacy-archive/juno-microwave-maps

Juno microwave sky maps and map-space companions

This dataset contains the 2025 LAMBDA release of Juno Microwave Radiometer sky maps and correlated-noise companions. Each of the 48 FITS bintables is one Parquet configuration named by its source filename stem. Its column is T, with the source table shape, float64 or int64 dtype, and row order. The six HDF5 companions add 20 dense-matrix configurations named by the source filename stem, __, and the HDF5 leaf name. Each leaf name is the sole Parquet column.

The release replaces LAMBDA's preliminary 2024 products. Juno's six radiometers R1 through R6 have central frequencies 600 MHz, 1.248 GHz, 2.597 GHz, 5.215 GHz, 10.004 GHz, and 21.9 GHz, each with approximately four per cent fractional bandwidth. Their approximate beam FWHM values are 19.7, 19.8, 11.9, 11.9, 11.9, and 10.7 degrees. The mapmaking removes long-timescale noise drifts, and for R1 and R2 also removes long-timescale gain drifts. Because the onboard absolute calibration is accurate only to plus or minus 6 Kelvin, the released monopoles are set to match the ARCADE2 fit to the CMB plus radio background.

Products and source structure

The unconvolved products are raw brightness-temperature maps in Kelvin. R1 and R2 are supplied at NSIDE 64 and 512; R3 through R6 are supplied at NSIDE 64. The CBC products are brightness-temperature maps convolved to a common 21-degree Gaussian FWHM at NSIDE 64. LAMBDA explicitly states that pixels exactly equal to zero in both map families have no sky coverage.

Matching hitmaps give the sample count per pixel. Diagonal thermal-noise maps estimate the average time-stream residual variance divided by the hitmap and are documented in Kelvin squared. Pointing-error products estimate random pointing-error variance in Kelvin squared. Simulated polarization-leakage products in Kelvin at NSIDE 32 result from viewing a polarized-sky simulation with the Juno scan strategy and measured leakage patterns. Pixelization-noise corrections in Kelvin at NSIDE 64 should be added to the raw maps where that correction is wanted; the mirror does not apply them.

Every FITS source has an empty primary HDU and one bintable named xtension. Its sole column is T. Ordinary maps use 1024D; hitmaps use 1024K. NSIDE 64 tables have 48 rows, NSIDE 512 tables have 3,072 rows, and NSIDE 32 tables have 12 rows. Each Parquet cell remains a fixed list of 1,024 elements. Element j of row i is HEALPix RING pixel i * 1024 + j. The FITS files omit coordinate and unit keywords. Embedded metadata records Galactic coordinates and documented physical units with evidence bases instead of altering the source column. Arrow field metadata carries Kelvin on the 14 raw and convolved temperature configurations, six polarization-leakage products, and six pixelization-noise corrections. It carries Kelvin^2 on the eight diagonal thermal-noise and six pointing-error-variance configurations. The eight hitmaps remain unitless.

The raw and convolved zero codes carry LAMBDA's documented no-coverage meaning. For companions without an archive declaration, observed zero or positive infinity codes are recorded as measured and meaning-free. This makes masking reproducible without inventing semantics.

Correlated gain and noise errors dominate the diagonal thermal variance on large angular scales. The R1 and R2 NSIDE=64 maps have substantial Galactic-plane pixelization artifacts; comparisons with maps made using a different scan pattern can mistake those artifacts for angular variation in synchrotron spectral index. The released correction maps estimate but do not eliminate this model-dependent systematic.

The receivers are singly polarized, so polarization leakage can contaminate the intensity maps. Spacecraft spin moves a beam by about one degree during each 0.1-second integration, producing scan smearing. Pointing-error estimates assume that the microwave receivers share the transmitter's approximately 0.25-degree pointing uncertainty and use an approximate beam-convolved sky model.

How to use

python -m venv .venv && .venv/bin/pip install datasets huggingface_hub pyarrow

from datasets import load_dataset
dataset = load_dataset("astro-legacy-archive/juno-microwave-maps", "R1_map_Nside64", split="train[:1]", columns=["T"])
row = dataset[0]
print(row["T"][:3])

[8.499069360640542, 0.0, 9.190772131077132]

import json
from huggingface_hub import hf_hub_download
import pyarrow.parquet as pq
path = hf_hub_download("astro-legacy-archive/juno-microwave-maps", "R1_map_Nside64.parquet", repo_type="dataset")
print(json.loads(pq.read_schema(path).metadata[b"healpix_map"])["schema"])

astro-legacy-archive/healpix-map

This representative configuration preserves the source’s 48-by-1,024 layout. The embedded document records its geometry, optional unit, coverage records, and pixel_rule; consumers must branch on absent units or coverage codes and apply the recorded packing rule.

Correlated-noise companions

The six R*_SVD_Nside64.h5 files are converted as 20 dense-matrix configurations. Each singular_values vector is one fixed-list row of length 50. Each singular_vectors matrix is 49,152 rows of fixed lists of length 50. The HDF5 datasets have no dimension labels; metadata preserves that absence and their exact float64 shape and C-order serialization. R1 and R2 each contain float64 singular_values with shape 50 and singular_vectors with shape 49152 by 50. LAMBDA documents singular values in Kelvin squared and defines the correlated map covariance as vectors * singular_values * vectors.T.

R3 through R6 separately contain offset_singular_values, offset_singular_vectors, gain_singular_values, and gain_singular_vectors, with corresponding shapes 50 and 49152 by 50. Their covariance is the sum of the offset and gain terms. The files and datasets have no HDF5 attributes. The rank-50 approximation retains about 90 percent of the correlated covariance power. They use dense-matrix 1.0.0 rather than the scalar statistical-product or HEALPix-map schemas.

Provenance, rights, and citation

HEASARC states verbatim:

HEASARC materials are all available freely for your use.

This is a free-use statement rather than a named formal licence.

The product page is https://lambda.gsfc.nasa.gov/product/foreground/fg_juno_info.html and the exact 54-file manifest is on https://lambda.gsfc.nasa.gov/product/foreground/fg_juno_get.html. The source pins are:

Source file	Bytes	SHA-256
R1_CBC_map_Nside64.fits	400320	02f98ca26ebff9e9acc795edb70387649c98fdf5e7aa48ab2f0d7c6691d27589
R1_Diagonal_Thermal_Noise_Nside512.fits	25174080	e2458c2b6a7b33fd0b3671c03ff1712cac6b04d155a8a8de9f9c26680158da62
R1_Diagonal_Thermal_Noise_Nside64.fits	400320	9117ab6472afe6f87dd81e1b6d4e5ef1178e1dda6605b3f097405e590cc9e193
R1_Pointing_Error_Variance.fits	400320	acfd8fc8e853956ccccb79230eac730d79ae6dac85f77b16fcc492f51000ef97
R1_SVD_Nside64.h5	19663248	aff496d4478728f77623cb194046fb152e6069531b658460049787282115440b
R1_Sim_Polarization_Leakage.fits	106560	77d4d7040fcc83cf3fe3c73a76f05890839be5a7f4ccd78039b898d832e5f5e0
R1_hitmap_Nside512.fits	25174080	cd2532262c5797bdcef8bfd79b833e43fd014d88acd29a8c4f793e10807e0339
R1_hitmap_Nside64.fits	400320	f5b386fce85f59314a28d8114186c3d694b081a748547182bc71207abb3a644d
R1_map_Nside512.fits	25174080	9f4b35c16e24e75b97ac40814a5f22606d10abb5e6d4c5d89f079b2dbb3cac0d
R1_map_Nside64.fits	400320	0941839ee1aa24e5ba3922e0bbf87bc6e0baf6b561312ff855a7f858eabdd677
R1_pixelization_noise_correction_Nside64.fits	400320	a54f93425855754477add3ea03e5ea0620897d170903794adafde02f05fe824f
R2_CBC_map_Nside64.fits	400320	0b7d92376faf4d591cee09b53a42c4724b0c03aa399b961e69ec089178bca2a3
R2_Diagonal_Thermal_Noise_Nside512.fits	25174080	fad1057083cbbde663b79ab0e30f17e4c38fa57eb4a12fbaebb64008bebf32e6
R2_Diagonal_Thermal_Noise_Nside64.fits	400320	0ec620892e1bf1418162eca60d326c404a1628736bcbe4ff6d5b54747190082b
R2_Pointing_Error_Variance.fits	400320	8fe0231daa498aaf9840b9f2a08c2732e4313c0ed4177b24c8b17f1e69089f36
R2_SVD_Nside64.h5	19663248	35f18f55de131600f62edbc141ea7d2ca0e11aed7062b21bec13ac61f35c1774
R2_Sim_Polarization_Leakage.fits	106560	9a9a57483cff8a146ac2e40a0f01cd1a545096f26579d40c2799c638a561a9f2
R2_hitmap_Nside512.fits	25174080	bd44388348e633c5623c5c47e052e95857c44519869921c2fda03176dfe241d4
R2_hitmap_Nside64.fits	400320	a6c4c5ccb21e61c336ff509bc2db29145a8f3229e91c1ae9bf85a7f62389b8d1
R2_map_Nside512.fits	25174080	ddee31de59984b060269cd3274665ac5300fd9a0cbff8a6c39401d029e7e5ff6
R2_map_Nside64.fits	400320	47b7d9646812ae315451f365f437bdffef748230afa978b1e28cd91b61f70606
R2_pixelization_noise_correction_Nside64.fits	400320	7950d9db99061b478df06ec5e69daf41de6f3448f82c12dea77ff5743b52a02c
R3_CBC_map_Nside64.fits	400320	1b6e5cda3f04c905975909e65e682840d176bd7b6370e1a9f33f582ef1e426f6
R3_Diagonal_Thermal_Noise_Nside64.fits	400320	3834b381688f665734f7292b6f7dc8b0857fcdb69bea5f84714cd72ff5c02f0b
R3_Pointing_Error_Variance.fits	400320	c14629c8e91e1905be73ab87073d514c1d1deb2579f511d8b88e89f6522f8370
R3_SVD_Nside64.h5	39326496	74efab80a4d659e466adadfc05e26665108258bdf7827dbc79ede2965e583274
R3_Sim_Polarization_Leakage.fits	106560	119d82f1585f03970b448337a60d83446c51207878712ecfc003b76110d6d09c
R3_hitmap_Nside64.fits	400320	9d46c7761a12f972d1826909d90734298a93e0a742e47275be8d502adf409846
R3_map_Nside64.fits	400320	b241768fdd4d1f0b4eec96db70997c45b51d6ee8d8dc3934e9d0ab8b0221de6f
R3_pixelization_noise_correction_Nside64.fits	400320	6cb26216aa93d0e8a4d127531c9f77313061b96043982d0b6868c2978f7aa7bf
R4_CBC_map_Nside64.fits	400320	0a5cd96dd098d8dc5ec4f2c6e0f9d70426bd9ebe57b0b58c6cfa6f876e65afa7
R4_Diagonal_Thermal_Noise_Nside64.fits	400320	6c28cfd5ff60b43b2f127f149fb2f3ece99db14896b037122fe591ed912a9761
R4_Pointing_Error_Variance.fits	400320	95298f99df875040818dbe5746ccbb374761920edd905403623f99f6d4b997fb
R4_SVD_Nside64.h5	39326496	15829d97a24e9dcf2d6685dd7c6e5f81ba726b2abe004c43a34947298439be58
R4_Sim_Polarization_Leakage.fits	106560	407d98ae3c8843acb1e7c19557fe21d914834657b38c2adcf4489eec058758f4
R4_hitmap_Nside64.fits	400320	0732090be0222bf021fdaf1a575206e7b3367d20fb724e66857713c1762d1415
R4_map_Nside64.fits	400320	8a121f29557d8de387e439d783d0aa0541f095dc292a73f2a2c06605d52df51e
R4_pixelization_noise_correction_Nside64.fits	400320	a1dcc0fb21ae3c640d2c428a6139a4fd41a52b8aeacbbeb1f6adf216dde443ed
R5_CBC_map_Nside64.fits	400320	1fbcb828a68a2b1e906a47e4626b50f61ea28d719e531c6c1647fdd9967a00b5
R5_Diagonal_Thermal_Noise_Nside64.fits	400320	9cf47cb6f9fade909d6c09816b92815d669bdc8da6b31cc9afeb8f49bf5a3aeb
R5_Pointing_Error_Variance.fits	400320	1f9d308d8ca9cf13b7a36380905187ed8e6c5fdb7dd7e649fff6be4058cb4964
R5_SVD_Nside64.h5	39326496	2d1e077e15e0846ec2c220e4fed21dd517738580b3253ff846e6967ec01c83b8
R5_Sim_Polarization_Leakage.fits	106560	9f5df6cecc3e131e7e904634cb7351fb7c50a4bf8319c8c871303510d22df1bf
R5_hitmap_Nside64.fits	400320	976d3f1627447b77d03f0e2302383102bb65581012f9237d057883235667bf35
R5_map_Nside64.fits	400320	66d9413b4b069de37146c538da1894768e709bf9e73b16ee520bc29eb40533d0
R5_pixelization_noise_correction_Nside64.fits	400320	320e19c9173b4322143edb297fd8162ee56578a575e2e8feb2540387bd888b66
R6_CBC_map_Nside64.fits	400320	b1195c1f45e60bc4cf6c27ac46ba0a2698e50af55d019bc6dba471d5c1518cae
R6_Diagonal_Thermal_Noise_Nside64.fits	400320	7bae14340759632e3642e2e5b09268fe3c782f276b477dbe8ab524326a56843c
R6_Pointing_Error_Variance.fits	400320	e2c7fd1f4f62423ddd320e73a5a8fbf5a2baf0b448d34109fd6824906158f5be
R6_SVD_Nside64.h5	39326496	e242c7c2016117a36fc61acd444d3752694ae1bdf7d851bda9e3e0cf68af8174
R6_Sim_Polarization_Leakage.fits	106560	f6d0b3bac05349bf95318d080384bec8957491ced08b7190881dbd5a4226a0cf
R6_hitmap_Nside64.fits	400320	7e916c2cb048ac008ebfb839672227144f29a02f78721a2bee0c059bebabbf8e
R6_map_Nside64.fits	400320	7ce369f8c173abab31760dccd4f4925c324b31083eb367c8c4c10a77c2cd66bc
R6_pixelization_noise_correction_Nside64.fits	400320	bb2bce46851bbb8a2553168f9e95d81bd834d488ba31031d5b4e3919cbd76e4b

All converted sizes and hashes and the complete HDF5 census are recorded in facts.yaml.

The article's CC BY licence does not license the data, and no named product licence is published. The HEASARC free-use statement quoted above is represented as other. Cite Anderson et al. (2025), “The Radio and Microwave Sky as Seen by Juno on its Mission to Jupiter”, ApJ 982, 118, doi:10.3847/1538-4357/adba62.

LAMBDA requests the following acknowledgement:

We acknowledge the use of the Legacy Archive for Microwave Background Data Analysis (LAMBDA), part of the High Energy Astrophysics Science Archive Center (HEASARC). HEASARC/LAMBDA is a service of the Astrophysics Science Division at the NASA Goddard Space Flight Center.

Errata and requests

To report an erratum, propose a correction, or ask a question about this dataset, open a Discussion or Pull Request in its Community tab; posting requires a free Hugging Face account. Dataset requests and archive-wide questions may be posted in the README space's Community tab or the Community tab of any dataset. Confirmed corrections are made in the source conversion tools and published by rebuilding the dataset.