Wine and Cheese Fall 2020 - Revision history

Kdkuntz at 16:08, 27 November 2020

2020-11-27T16:08:01Z

← Older revision		Revision as of 16:08, 27 November 2020
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	'''The Formation of Ultra-Diffuse Galaxies in the Field'''		'''The Formation of Ultra-Diffuse Galaxies in the Field'''
	Although low surface brightness (LSB) galaxies make up a significant fraction of the galaxy population, it is only within the last few years that they have been studied in large numbers. Consequently, the methods by which they form and evolve, as well as the extent to which these processes fit within the commonly accepted paradigms of galaxy evolution and cosmology lack a consensus. In this talk, I discuss the properties and evolution of ultra-diffuse galaxies (UDGs), a subset of the LSB galaxy population characterized by dwarf-like luminosities, but light profiles that can extend as far as those of Milky-Way-mass galaxies. In the Romulus25 cosmological simulation, we find that isolated UDGs are the products of early major mergers that produce a temporary boost in spin and cause star-forming gas to migrate from the centers of the galaxies to larger radii.		Although low surface brightness (LSB) galaxies make up a significant fraction of the galaxy population, it is only within the last few years that they have been studied in large numbers. Consequently, the methods by which they form and evolve, as well as the extent to which these processes fit within the commonly accepted paradigms of galaxy evolution and cosmology lack a consensus. In this talk, I discuss the properties and evolution of ultra-diffuse galaxies (UDGs), a subset of the LSB galaxy population characterized by dwarf-like luminosities, but light profiles that can extend as far as those of Milky-Way-mass galaxies. In the Romulus25 cosmological simulation, we find that isolated UDGs are the products of early major mergers that produce a temporary boost in spin and cause star-forming gas to migrate from the centers of the galaxies to larger radii.

			=7 December=
			==Peter Kurczynski (NASA)==
			'''Bridges to New Worlds: Astrophysics Themes at NASA'''
			Have you ever wondered "How does NASA Astrophysics work?" or "How can I talk to NASA Astrophysics?" NASA supports telescope time at Keck Observatory in support of NASA Astrophysics objectives. NASA interfaces with the astrophysics research community via three main science themes: Exoplanet Exploration (ExEP), Physics of the Cosmos (PCOS) and Cosmic Origins (COR). These themes organize scientific and technical interests and perform analyses that are critical to the agency. This presentation will highlight opportunties and the benefits for researchers, especially early-career researchers to become involved.

Kdkuntz at 13:46, 24 November 2020

2020-11-24T13:46:49Z

← Older revision		Revision as of 13:46, 24 November 2020
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	'''Revealing structural disturbance in post-starburst galaxies with HST'''<br>		'''Revealing structural disturbance in post-starburst galaxies with HST'''<br>
	Most galaxies belong to one of two types: star-forming disks (SFGs), or quiescent bulge-dominated galaxies (QGs) that used to be star-forming. The reasons SFGs stop forming stars and evolve into QGs are still disputed, but one is certain: a complex interplay of different processes is required to both quench star formation, and change the morphology of a galaxy. The search for the driver of galaxy evolution is made more difficult by the rapidity of this evolution, and the relative dearth of galaxies undergoing this transition. Post-starburst galaxies serve as an essential link between SFGs and QGs, having just stopped forming stars. We study a special sample of 23 post-starbursts that have 1) ceased star formation in the last Gyr, 2) have ongoing energetic processes ionizing their gas, and 3) still retain significant fractions of molecular gas. To probe the link between morphology and star formation, we perform a detailed morphological analysis of their optical HST and SDSS imaging. We find that our sample is much more structurally disturbed in HST imaging than quiescent or star-forming galaxies, but these disturbances are not seen with SDSS. This shows that a violent origin of these galaxies was initially missed by lower-resolution SDSS-based studies.		Most galaxies belong to one of two types: star-forming disks (SFGs), or quiescent bulge-dominated galaxies (QGs) that used to be star-forming. The reasons SFGs stop forming stars and evolve into QGs are still disputed, but one is certain: a complex interplay of different processes is required to both quench star formation, and change the morphology of a galaxy. The search for the driver of galaxy evolution is made more difficult by the rapidity of this evolution, and the relative dearth of galaxies undergoing this transition. Post-starburst galaxies serve as an essential link between SFGs and QGs, having just stopped forming stars. We study a special sample of 23 post-starbursts that have 1) ceased star formation in the last Gyr, 2) have ongoing energetic processes ionizing their gas, and 3) still retain significant fractions of molecular gas. To probe the link between morphology and star formation, we perform a detailed morphological analysis of their optical HST and SDSS imaging. We find that our sample is much more structurally disturbed in HST imaging than quiescent or star-forming galaxies, but these disturbances are not seen with SDSS. This shows that a violent origin of these galaxies was initially missed by lower-resolution SDSS-based studies.

			= 30 November =
			==Yossef Zenati (JHU)==
			'''Normal type Ia SNe from disruptions of hybrid He-CO WD by CO WD'''
			Type Ia supernovae (SNe) are thought to originate from the thermonuclear explosions of carbon-oxygen (CO) white dwarfs (WDs). The proposed progenitors of standard type Ia SNe have been studied for decades and can be, generally, divided into explosions of CO WDs accreting material from stellar non-degenerate companions (single-degenerate; SD models), and those arising from the explosive interaction of two CO WDs (double-degenerate; DD models). However, current models for the progenitors of such SNe fail to reproduce the diverse properties of the observed explosions, nor do they explain the inferred rates and the characteristics of the observed populations of type Ia SNe and their expected progenitors. Here we show that the little-studied mergers of CO-WDs with hybrid Helium-CO (He-CO) WDs can provide for a significant fraction of the normal type Ia SNe. Here we use detailed thermonuclear-hydrodynamical and radiative-transfer models to show that a wide range of mergers of CO WDs with hybrid He-CO WDs can give rise to normal type Ia SNe. We find that such He-enriched mergers give rise to explosions for which the synthetic light-curves and spectra resemble those of observed type Ia SNe, and in particular, they can produce a wide range of peak-luminosities, MB(MR)~ 18.4 to 19.2 (~ 18.5 to 19.45), consistent with those observed for normal type Ia SNe. Moreover, our population synthesis models show that, together with the contribution from mergers of massive double CO-WDs (producing the more luminous SNe), they can potentially reproduce the full range of type Ia SNe, their rate and delay-time distribution.

			==Anna Wright (JHU)==
			'''The Formation of Ultra-Diffuse Galaxies in the Field'''
			Although low surface brightness (LSB) galaxies make up a significant fraction of the galaxy population, it is only within the last few years that they have been studied in large numbers. Consequently, the methods by which they form and evolve, as well as the extent to which these processes fit within the commonly accepted paradigms of galaxy evolution and cosmology lack a consensus. In this talk, I discuss the properties and evolution of ultra-diffuse galaxies (UDGs), a subset of the LSB galaxy population characterized by dwarf-like luminosities, but light profiles that can extend as far as those of Milky-Way-mass galaxies. In the Romulus25 cosmological simulation, we find that isolated UDGs are the products of early major mergers that produce a temporary boost in spin and cause star-forming gas to migrate from the centers of the galaxies to larger radii.

Kdkuntz at 22:27, 13 November 2020

2020-11-13T22:27:42Z

← Older revision		Revision as of 22:27, 13 November 2020
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	==Liza Sazanova (JHU) ==		==Liza Sazanova (JHU) ==
	'''Revealing structural disturbance in post-starburst galaxies with HST'''<br>		'''Revealing structural disturbance in post-starburst galaxies with HST'''<br>
	Most galaxies belong to one of two types: star-forming disks (SFGs), or quiescent bulge-dominated galaxies (QGs) that used to be star-forming. The reasons SFGs stop forming stars and evolve into QGs are still disputed, but one is certain: a complex interplay of different processes is required to both quench star formation, and change the morphology of a galaxy. The search for the driver of galaxy evolution is made more difficult by the rapidity of this evolution, and the relative dearth of galaxies undergoing this transition. Post-starburst galaxies serve as an essential link between SFGs and QGs, having just stopped forming stars. We study a special sample of 23 post-starbursts that have 1) ceased star formation in the last Gyr, 2) have ongoing energetic processes ionizing their gas, and 3) still retain significant fractions of molecular gas. To probe the link between morphology and star formation, we perform a detailed morphological analysis of their optical HST and SDSS imaging. We find that our sample is much more structurally disturbed in HST imaging than quiescent or star-forming galaxies, but these disturbances are not seen with SDSS. This shows that a violent origin of these galaxies was initially missed by lower-resolution SDSS-based studies.		Most galaxies belong to one of two types: star-forming disks (SFGs), or quiescent bulge-dominated galaxies (QGs) that used to be star-forming. The reasons SFGs stop forming stars and evolve into QGs are still disputed, but one is certain: a complex interplay of different processes is required to both quench star formation, and change the morphology of a galaxy. The search for the driver of galaxy evolution is made more difficult by the rapidity of this evolution, and the relative dearth of galaxies undergoing this transition. Post-starburst galaxies serve as an essential link between SFGs and QGs, having just stopped forming stars. We study a special sample of 23 post-starbursts that have 1) ceased star formation in the last Gyr, 2) have ongoing energetic processes ionizing their gas, and 3) still retain significant fractions of molecular gas. To probe the link between morphology and star formation, we perform a detailed morphological analysis of their optical HST and SDSS imaging. We find that our sample is much more structurally disturbed in HST imaging than quiescent or star-forming galaxies, but these disturbances are not seen with SDSS. This shows that a violent origin of these galaxies was initially missed by lower-resolution SDSS-based studies.

Kdkuntz: /* Liza Sazanova (JHU) */

2020-11-13T22:27:12Z

Liza Sazanova (JHU)

← Older revision		Revision as of 22:27, 13 November 2020
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	==Liza Sazanova (JHU) ==		==Liza Sazanova (JHU) ==
	'''~~TBD~~'''<br>		'''Revealing structural disturbance in post-starburst galaxies with HST'''<br>
			Most galaxies belong to one of two types: star-forming disks (SFGs), or quiescent bulge-dominated galaxies (QGs) that used to be star-forming. The reasons SFGs stop forming stars and evolve into QGs are still disputed, but one is certain: a complex interplay of different processes is required to both quench star formation, and change the morphology of a galaxy. The search for the driver of galaxy evolution is made more difficult by the rapidity of this evolution, and the relative dearth of galaxies undergoing this transition. Post-starburst galaxies serve as an essential link between SFGs and QGs, having just stopped forming stars. We study a special sample of 23 post-starbursts that have 1) ceased star formation in the last Gyr, 2) have ongoing energetic processes ionizing their gas, and 3) still retain significant fractions of molecular gas. To probe the link between morphology and star formation, we perform a detailed morphological analysis of their optical HST and SDSS imaging. We find that our sample is much more structurally disturbed in HST imaging than quiescent or star-forming galaxies, but these disturbances are not seen with SDSS. This shows that a violent origin of these galaxies was initially missed by lower-resolution SDSS-based studies.

Kdkuntz: /* Liza Sazanova (JHU) */

2020-11-13T04:21:57Z

Liza Sazanova (JHU)

← Older revision		Revision as of 04:21, 13 November 2020
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	==Liza Sazanova (JHU) ==		==Liza Sazanova (JHU) ==
	''' '''<br>		'''TBD'''<br>

Kdkuntz at 04:21, 13 November 2020

2020-11-13T04:21:28Z

← Older revision		Revision as of 04:21, 13 November 2020
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	''' Disentangling the Cosmic Web with Fast Radio Bursts'''<br>		''' Disentangling the Cosmic Web with Fast Radio Bursts'''<br>
	I will report on a set of new, well-localized (<1”) fast radio bursts (FRBs) discovered primarily by the ASKAP telescope. Nearly each of these events is coincident with a luminous galaxy which we designate as the host. Spectra of the galaxies establish the FRB redshifts and offer a first assessment of the dispersion measure vs. redshift (aka The Maquart Relation). This yields a new estimate of the cosmic baryon density for the low-z universe, consistent with measurements from BBN and the CMB, i.e. the so-called “missing baryons problem” has been resolved! Last (time permitting), we analyze the rotation measure and pulse width of one FRB to study the magnetic field and density of gas in a foreground galaxy halo.		I will report on a set of new, well-localized (<1”) fast radio bursts (FRBs) discovered primarily by the ASKAP telescope. Nearly each of these events is coincident with a luminous galaxy which we designate as the host. Spectra of the galaxies establish the FRB redshifts and offer a first assessment of the dispersion measure vs. redshift (aka The Maquart Relation). This yields a new estimate of the cosmic baryon density for the low-z universe, consistent with measurements from BBN and the CMB, i.e. the so-called “missing baryons problem” has been resolved! Last (time permitting), we analyze the rotation measure and pulse width of one FRB to study the magnetic field and density of gas in a foreground galaxy halo.

			= 16 November =
			== Lingyuan Ji (JHU) ==
			'''Standard Model Prediction for Cosmological 21cm Circular Polarization'''<br>
			Before cosmic reionization, hydrogen atoms acquire a spin polarization quadrupole through interaction with the anisotropic 21-cm radiation field. The interaction of this quadrupole with anisotropies in the cosmic microwave background (CMB) radiation field gives a net spin orientation to the hydrogen atoms. The 21-cm radiation emitted by these spin-oriented hydrogen atoms is circularly polarized. Here, we reformulate succinctly the derivation of the expression for this circular polarization in terms of Cartesian (rather than spherical) tensors. We then compute the angular power spectrum of the observed Stokes-V parameter in the standard ΛCDM cosmological model and show how it depends on redshift, or equivalently, the observed frequency.

			==Carolina Nunez (JHU)==
			'''The Cosmology Large Angular Scale Surveyor (CLASS): Instrument Overview and Internal Data Consistency Checks'''<br>
			The Cosmology Large Angular Scale Surveyor (CLASS) is a polarization-sensitive telescope array located at an altitude of 5,200 m in the Chilean Atacama Desert. CLASS is designed to characterize primordial gravitational waves and constrain the optical depth to reionization, through detection of "B-mode" (curl component) and "E-mode" (divergence component) polarization patterns in the Cosmic Microwave Background (CMB) over large angular scales. Currently, all four CLASS frequencies are fielded across three telescopes: the 40 GHz (Q-band) focal plane achieved first light in June 2016; the first of two 90 GHz (W-band) focal planes achieved first light in May 2018; and the high frequency (HF) dichroic 150/220 GHz focal plane achieved first light in September 2019. The detection of B-mode polarization over large angular scales is a particularly challenging measurement, requiring both high sensitivity and control of systematics. I will provide a brief overview of the CLASS science goals, the instrument design required to achieve them, and finally I will discuss the statistical tools used to confirm internal consistency of the data.

			==Liza Sazanova (JHU) ==
			''' '''<br>

Kdkuntz at 14:34, 28 October 2020

2020-10-28T14:34:23Z

← Older revision		Revision as of 14:34, 28 October 2020
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	'''Gravitational-Wave Astronomy Five Years Since the First Detection'''<br>		'''Gravitational-Wave Astronomy Five Years Since the First Detection'''<br>
	Five years after the first gravitational-wave detection of a binary black-hole merger, we consider such detections routine and we are focusing on extracting population astrophysical information from a rapidly growing sample of black hole mergers. In parallel, gravitational-wave observations continue to surprise us with discoveries of mergers with unexpected properties, revealing novel aspects of compact object formation and evolution. In this talk I will summarize where our understanding stands at present, focus on the exceptional sources announced so far, and discuss what we anticipate for the future.		Five years after the first gravitational-wave detection of a binary black-hole merger, we consider such detections routine and we are focusing on extracting population astrophysical information from a rapidly growing sample of black hole mergers. In parallel, gravitational-wave observations continue to surprise us with discoveries of mergers with unexpected properties, revealing novel aspects of compact object formation and evolution. In this talk I will summarize where our understanding stands at present, focus on the exceptional sources announced so far, and discuss what we anticipate for the future.

			= 2 November =
			== J. Xavier Prochaska (UC Santa Cruz) ==
			''' Disentangling the Cosmic Web with Fast Radio Bursts'''<br>
			I will report on a set of new, well-localized (<1”) fast radio bursts (FRBs) discovered primarily by the ASKAP telescope. Nearly each of these events is coincident with a luminous galaxy which we designate as the host. Spectra of the galaxies establish the FRB redshifts and offer a first assessment of the dispersion measure vs. redshift (aka The Maquart Relation). This yields a new estimate of the cosmic baryon density for the low-z universe, consistent with measurements from BBN and the CMB, i.e. the so-called “missing baryons problem” has been resolved! Last (time permitting), we analyze the rotation measure and pulse width of one FRB to study the magnetic field and density of gas in a foreground galaxy halo.

Kdkuntz at 20:55, 21 October 2020

2020-10-21T20:55:44Z

← Older revision		Revision as of 20:55, 21 October 2020
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	'''Revealing progenitor system of Type Ia Supernovae with Kepler & TESS'''<br>		'''Revealing progenitor system of Type Ia Supernovae with Kepler & TESS'''<br>
	Despite its crucial role as standard candle in cosmological measurement, the progenitor system of Type Ia supernovae is still unclear. One of the most direct ways to studying progenitors of supernovae is to look into the very early time of explosion for subtle signatures. The 30-min cadence of Kepler & TESS Full-Frame Images provide adequate time resolution to reveal these features that are hard to be seen from ground-based observations. In this talk I'm going to present recent results from Kepler SNe Ia sample, especially SN2018oh and SN2018agk, and current progress of TESS Supernovae study.		Despite its crucial role as standard candle in cosmological measurement, the progenitor system of Type Ia supernovae is still unclear. One of the most direct ways to studying progenitors of supernovae is to look into the very early time of explosion for subtle signatures. The 30-min cadence of Kepler & TESS Full-Frame Images provide adequate time resolution to reveal these features that are hard to be seen from ground-based observations. In this talk I'm going to present recent results from Kepler SNe Ia sample, especially SN2018oh and SN2018agk, and current progress of TESS Supernovae study.

			= 26 October =
			== Vicky Kalogera (Northwestern) ==
			'''Gravitational-Wave Astronomy Five Years Since the First Detection'''<br>
			Five years after the first gravitational-wave detection of a binary black-hole merger, we consider such detections routine and we are focusing on extracting population astrophysical information from a rapidly growing sample of black hole mergers. In parallel, gravitational-wave observations continue to surprise us with discoveries of mergers with unexpected properties, revealing novel aspects of compact object formation and evolution. In this talk I will summarize where our understanding stands at present, focus on the exceptional sources announced so far, and discuss what we anticipate for the future.

Kdkuntz at 16:02, 12 October 2020

2020-10-12T16:02:09Z

← Older revision		Revision as of 16:02, 12 October 2020
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	'''A Clumpy Disc-Dominated Circumgalactic Medium of the Milky Way Seen in X-ray Emission'''<br>		'''A Clumpy Disc-Dominated Circumgalactic Medium of the Milky Way Seen in X-ray Emission'''<br>
	The Milky Way galaxy is surrounded by a circumgalactic medium (CGM) that may play a key role in galaxy evolution as the source of gas for star formation and a repository of metals and energy produced by star formation and nuclear activity. The CGM may also be a repository for baryons seen in the early universe, but undetected locally. The CGM has an ionized component at temperatures near 2 MK studied primarily in the soft X-ray band. Here we report a survey of the southern Galactic sky with a CubeSat-based soft X-ray spectrometer optimized to study diffuse soft X-ray emission. The X-ray emission is best fit with a disc-like model based on the radial profile of the surface density of molecular hydrogen, a tracer of star formation, suggesting that the X-ray emission is predominantly from hot plasma produced via stellar feedback. Strong variations in the X-ray emission on angular scales of 10° indicate that the CGM is clumpy. Addition of an extended, and possibly massive, halo component is needed to match the halo density inferred from other observations.		The Milky Way galaxy is surrounded by a circumgalactic medium (CGM) that may play a key role in galaxy evolution as the source of gas for star formation and a repository of metals and energy produced by star formation and nuclear activity. The CGM may also be a repository for baryons seen in the early universe, but undetected locally. The CGM has an ionized component at temperatures near 2 MK studied primarily in the soft X-ray band. Here we report a survey of the southern Galactic sky with a CubeSat-based soft X-ray spectrometer optimized to study diffuse soft X-ray emission. The X-ray emission is best fit with a disc-like model based on the radial profile of the surface density of molecular hydrogen, a tracer of star formation, suggesting that the X-ray emission is predominantly from hot plasma produced via stellar feedback. Strong variations in the X-ray emission on angular scales of 10° indicate that the CGM is clumpy. Addition of an extended, and possibly massive, halo component is needed to match the halo density inferred from other observations.

			= 19 October =
			== Brian Healy (JHU) ==
			'''The Orientation of Stellar Spins in Open Clusters'''<br>
			Measuring the distribution of stellar spin axis orientations in a coeval group of stars probes the physical processes underlying the stars' formation. Combining spectroscopic and photometric observations of open cluster members allows us to determine their degree of spin alignment. An isotropic distribution of spins implies a star-forming environment in which turbulence dominated ordered motion, while an aligned distribution suggests a more substantial contribution from rotation. In this talk, I will present our orientation results for the open cluster NGC 2516 and describe how they motivate a larger study of stellar spin in additional clusters.

			== Cyril Creque-Sarbinowski (JHU) ==
			'''Resonant Neutrino Self-Interactions'''<br>
			If neutrinos have self-interactions, these will induce scatterings between astrophysical and cosmic neutrinos. Prior work proposed to look for possible resulting resonance features in astrophysical neutrino spectra in order to seek a neutrino self-interaction which can be either diagonal in the neutrino flavor space or couple different neutrino flavors. The calculation of the astrophysical spectra involves either a Monte Carlo simulation or a computationally intensive numerical integration of an integro-partial-differential equation. As a result only limited regions of the neutrino self-interaction parameter space have been explored, and only flavor-diagonal self-interactions have been considered. Here, we present a fully analytic form for the astrophysical neutrino spectra for arbitrary neutrino number and arbitrary self-coupling matrix that accurately obtains the resonance features in the observable neutrino spectra. The results can be applied to calculations of the diffuse supernova neutrino background and of the spectrum from high-energy astrophysical neutrino sources. We illustrate with a few examples.

			== Qinan Wang (JHU) ==
			'''Revealing progenitor system of Type Ia Supernovae with Kepler & TESS'''<br>
			Despite its crucial role as standard candle in cosmological measurement, the progenitor system of Type Ia supernovae is still unclear. One of the most direct ways to studying progenitors of supernovae is to look into the very early time of explosion for subtle signatures. The 30-min cadence of Kepler & TESS Full-Frame Images provide adequate time resolution to reveal these features that are hard to be seen from ground-based observations. In this talk I'm going to present recent results from Kepler SNe Ia sample, especially SN2018oh and SN2018agk, and current progress of TESS Supernovae study.

Kdkuntz: /* Philip Kaaret (U Iowa) */

2020-10-05T22:39:32Z

Philip Kaaret (U Iowa)

← Older revision		Revision as of 22:39, 5 October 2020
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	== Philip Kaaret (U Iowa) ==		== Philip Kaaret (U Iowa) ==
	'''A Clumpy Disc-Dominated Circumgalactic Medium of the Milky Way Seen in X-ray Emission'''<br>		'''A Clumpy Disc-Dominated Circumgalactic Medium of the Milky Way Seen in X-ray Emission'''<br>
	The Milky Way galaxy is surrounded by a circumgalactic medium (CGM) that may play a key role in galaxy evolution as the source of gas for star formation and a repository of metals and energy produced by star formation and nuclear activity. The CGM may also be a repository for baryons seen in the early universe, but undetected locally. The CGM has an ionized component at temperatures near 2 MK studied primarily in the soft X-ray band. Here we report a survey of the southern Galactic sky with a CubeSat-based soft X-ray spectrometer optimized to study diffuse soft X-ray emission. The X-ray emission is best fit with a disc-like model based on the radial profile of the surface density of molecular hydrogen, a tracer of star formation, suggesting that the X-ray emission is predominantly from hot plasma produced via stellar feedback. Strong variations in the X-ray emission on angular scales of ~~10°�~~ indicate that the CGM is clumpy. Addition of an extended, and possibly massive, halo component is needed to match the halo density inferred from other observations.		The Milky Way galaxy is surrounded by a circumgalactic medium (CGM) that may play a key role in galaxy evolution as the source of gas for star formation and a repository of metals and energy produced by star formation and nuclear activity. The CGM may also be a repository for baryons seen in the early universe, but undetected locally. The CGM has an ionized component at temperatures near 2 MK studied primarily in the soft X-ray band. Here we report a survey of the southern Galactic sky with a CubeSat-based soft X-ray spectrometer optimized to study diffuse soft X-ray emission. The X-ray emission is best fit with a disc-like model based on the radial profile of the surface density of molecular hydrogen, a tracer of star formation, suggesting that the X-ray emission is predominantly from hot plasma produced via stellar feedback. Strong variations in the X-ray emission on angular scales of 10° indicate that the CGM is clumpy. Addition of an extended, and possibly massive, halo component is needed to match the halo density inferred from other observations.