Ray Garner 🏳️‍🌈
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astronoray.bsky.social
Ray Garner 🏳️‍🌈
@astronoray.bsky.social
70 followers 49 following 110 posts
Astronomer. Nature photographer. Astro postdoc at Texas A&M. he/him. Georgia native, College Station resident.
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astronoray.bsky.social
My very first undergrad presented the research that we worked on for the past year! I'm so proud of Liv and all of the work that she's put into this project, especially over the summer. Any future undergrads have some big shoes to fill! (And keep an eye out for the Research Note we'll publish soon!)
A smiling young woman with brightly colored hair and glasses standing in front of a poster.
July 30, 2025 at 6:18 PM
astronoray.bsky.social
So this is a strong piece of evidence for the hypothesis that what we call 5474 is actually a dwarf spiral and dwarf elliptical pair! They're likely bound to each other, but weakly interacting. How this plays into the M101-NGC 5474 interaction is anyone's guess.
March 3, 2025 at 4:35 PM
astronoray.bsky.social
The velocity maps show similar results. In each map, the bulge is a coherent structure and stands out in the velocity difference map at velocities of 20-40 km/s.

Our two methods agree! 🥳 There is a clear velocity offset between the disk and the bulge.
A series of maps showing how the velocities change across the field of view. The top row, from left to right show the stellar velocity, gas velocity, and velocity difference, while the bottom row shows the associated uncertainties. In the top row, the left and middle plots are have colors ranging from red to blue to indicate a change in velocity. At the center of these plots, the colors all change to a white color. The right plot in the top row and the bottom row of plots all have colors ranging from dark blue to green to pale yellow. The right plot in the top row shows a coherent group of green points at the center. In each plot, a red circle at the center outlines the position of the bulge.
March 3, 2025 at 4:35 PM
astronoray.bsky.social
Circular apertures ranging from 5" to 20" were placed on the bulge and we summed up all the light. Fitting the resulting spectra with pPXF and bootstrapping within the residuals shows a clear velocity difference between the stars (bulge) and gas (disk) of ~25 km/s!
A series of three histograms showing the distributions of bootstrapped values of (from left to right) the stellar velocities, gas velocities, and the velocity difference. Each panel contains four distributions in colors ranging from dark purple, blue, green, and light green. Above each distribution are errorbars marking the mean and standard deviation of each distribution and colored similarly.
March 3, 2025 at 4:35 PM
astronoray.bsky.social
30 Dor (left) is the largest, most booming star-forming region in our local group. Yesterday, I attended a talk that, using JWST images, found ~1300 super star clusters in M82 (right) with similar masses to 30 Dor.

That little galaxy is BOOMING!
An image of the star-forming region 30 Doradus. At the center is a tightly-packed cluster of blue-white stars. Surrounding that cluster are tendrils of white or beige colored tendrils of gas and dust. Further out the tendrils are colored red, indicating a different composition. This is all set upon a background of black space pockmarked with tiny, more distant stars. An image of the starbursting galaxy Messier 82. Stretching across the image is the main disk of the galaxy, mostly a diffuse white color with a few dark dust lanes in the disk. Coming out from the center of the galaxy, perpendicular to the disk, are two "cones" of red filaments of ionized gas. The southern cone is more pronounced than the northern cone. The entire scene is on a backdrop of black space pockmarked with tiny distant stars.
February 19, 2025 at 3:31 PM
astronoray.bsky.social
Read this exchange in a Star Wars book I'm reading and I thought it worth sharing.
Text that reads: (first speaker) "They will not be reasoned with or made to see the error of their ways but will instead pervert law and call it justice; confound wisdom with wickedness; commit great evils and name them benevolence." (second speaker) "I know. And so we must ever be a beacon of light for those out in the roaring seas, a candle of life for those encircled by the dark, a warming fire for those who will not succumb to the engulfing night. To do what is right does not require perfection, only resolve."
February 16, 2025 at 6:41 PM
astronoray.bsky.social
Oh how times (and logos) change! I spent some time at CWRU this week and shared some of the work I've been up to as a postdoc in SIGNALS. I also got to sit down with @chrismihos.bsky.social and convince him we still have some work to do together! It was great seeing everyone and reminiscing!
The author, astronoray, a young man with light sky, dark brown hair, and glasses is taking a selfie in front of a Case Western Reserve University sign. He is wearing a black T-shirt with rainbow-colored text that reads "There's all in y'all" (partially obscured). The university is mounted on a stone wall with neatly arranged red and yellow flowers in front of it. A beige building with large windows and a museum banner reading "How Medicine Became Modern" is visible in the background. The sky is clear and blue, and the trees around the area are lush and green. The poster, Astronoray, a young man with light skin, dark brown hair, and glasses is taking a selfie in front of a Case Western Reserve University sign. He is wearing a black jacket with a gray hoodie underneath and a maroon shirt. The sign is blue with white lettering, and behind it is a beige stone building with large windows. The ground is covered with patches of snow and ice, and the plants in front of the sign are dormant, suggesting a winter setting. The man has a slight smile and appears to be enjoying the moment.
February 13, 2025 at 3:48 PM
astronoray.bsky.social
No, unless it is a judicial warrant signed by a judge, you do not have to comply. ICE typically only carries administrative warrants which do not allow access to non-public areas. Know your rights!
Text that reads, "Law enforcement agencies, including U.S. Immigration and Customs Enforcement (ICE), are permitted to enter public areas at each of our campuses and teaching sites. Access to nonpublic areas, like on-campus residence halls and dormitories, typically requires a search warrant. If you are presented with a warrant to access a restricted area by a law enforcement officer, please listen to their instructions, comply and immediately notify the University Police Department or the designated public safety contact for your respective location."
February 6, 2025 at 4:23 PM
astronoray.bsky.social
I'm entirely convinced that Saturday will be January 32nd.
A poem titled "Mnemonic" by Brian Bilston. It reads, Thirty days hath September, April, June and November. Unless a leap year is its fate, February hath twenty-eight. All the rest hath three days more, excepting January, which hath six thousand, one hundred and eighty-four.
January 30, 2025 at 3:46 AM
astronoray.bsky.social
"There she stands, so tall and mighty
Her gaze facing the East
At her back our doors are closing
As we grin and bare our teeth
On the wind the wolves are howling
She cries, they're drawn near
Well turn around, turn around my darling
Oh, the wolves are here"
"The Wolves" by Watchhouse
The Statue of Liberty in front of a cloudy sky. Water of the bay lines the bottom of the image. The American flag is unfurled and flying in the background, in the right of the image. There's a melancholy feel of the image.
January 20, 2025 at 6:06 PM
astronoray.bsky.social
Put here without comment.
A tumblr post by user brionysea that reads, "usamericans, do you remember in the incredibles when syndrome made the robot go haywire just so he could swoop in and 'save the day'"
January 20, 2025 at 2:47 AM
astronoray.bsky.social
when the 'save' button doesn't take me directly to my files
A clip from the TV show "The Simpsons" showing Grandpa Simpson in a newspaper. The newspaper headline reads "Old Man Yells At Cloud". Grandpa Simpson has his fist raised and it looks like he is yelling. The logos of several Cloud-based services (Google Drive, iCloud, OneDrive, Adobe, etc.) are floating above his fist.
December 10, 2024 at 3:09 PM
astronoray.bsky.social
They get one ghost with a silencer. (Out of network fees apply.)
A tweet from from @VeryBadLlama that reads, "in today's fast-paced world we simply don't have time for CEOs to be visited by three Christmas ghosts"
December 7, 2024 at 7:42 PM
astronoray.bsky.social
Incorporating dust extinction through the color excess, E(B-V), into the anti-correlation does reduce the scatter significantly. This panel is a "fundamental plane" combining dust and O/H on the x-axis and ion. param. on the y-axis. The scatter went down from 0.3 to 0.2!
Scatter plot showing the relationship between the ionization parameter (log U) and a linear combination of oxygen abundance (12 + log(O/H)) and color excess (E(B-V)). Several data points are plotted, with green density contours on top indicating concentration of points. A black line is also plotted showing a general upwards trend. The x-axis ranges from approximately -3.2 to -2.4, and the y-axis ranges from -5 to -1.5.
December 3, 2024 at 4:40 PM
astronoray.bsky.social
But now, what of the correlation? Theoretical predictions say there should be a slope of -0.8. When we plot ours, we get a slope of -0.67, an anti-correlation!

What causes this? At high O/H, stellar winds are more opaque and scatter photons better, leading to lower ion. param.! (Dopita+06)
A figure of three panels from left to right. All panels are showing the relationship between the ionization parameter (log U) and oxygen abundance (12 + log(O/H)). The x-axis ranges from 8 to 9.5, while the y-axis ranges from -5 to -1.5. In the left and middle panels, several small black points are plotted with larger black points on top, representing the binned data. Black lines and shaded regions have been fitted and encompass most of the black points. Other colored lines are plotted for comparison. The left panel reads "H-alpha S/N greater than or equal to 0" at the top, while the middle panel reads "H-alpha S/N greater than or equal to 15" at the top. The right panel is a density plot with a color gradient changing from light blue (low S/N) to orange (high S/N).
December 3, 2024 at 4:40 PM
astronoray.bsky.social
Another test of our methods was to reproduce observed radial gradients in O/H, ion. param., and N/O. Turns out we can reproduce these fairly well within the uncertainties!
A figure of three panels showing radial gradients of three different properties. From top to bottom: the oxygen abundance (12 + log(O/H)), the ionization parameter (log U), and the nitrogen-to-oxygen abundance (log(N/O)). In each panel, the x-axis is the radial distance in terms of the R25 radius on the bottom and in kiloparsecs on the top. The bottom x-axis ranges from 0 to 1.5, while the top x-axis ranges from 0 to 20. The top panel shows the radial oxygen abundance gradient scatter plot. There are several large black points representing the binned data. A black line and shaded region encompasses the black points and shows a general downward trend. Other colored lines are also plotted for comparison. The y-axis ranges from 8.0 to 9.5. The middle panel shows the ionization parameter (log U) radial gradient. There are several large black points representing the binned data. A black line and shaded region encompass most of the data points and slopes generally upwards. There are two red lines for comparison. The y-axis ranges from -5.0 to -1.0. The bottom panel shows the nitrogen-to-oxygen abundance (log(N/O)) radial gradient. There are several large black points representing the binned data. A black line and shaded region encompass all of the data points and slopes generally downwards. Other colored lines are included for comparison. The y-axis ranges from -2.0 to 0.5.
December 3, 2024 at 4:40 PM
astronoray.bsky.social
That means that I created my own Cloudy models (with help of Grace Olivier!) and applied a Bayesian code called NebulaBayes to associate a model with each HII region. This was a lot of work, picking priors, likelihoods, and error weighting! But comparing with CHAOS shows a good agreement!
A panel of 6 subplots, each showing a different physical property, but all comparing the CHAOS observations to the Cloudy+NebulaBayes modeling. From top to bottom, left to right, the panels show the: [NII]/[OII] ratio, the [OIII]/[OII] ratio, the ([OIII] + [OII]/Hbeta) ratio, the nitrogen abundance (log(N/H)), the [SIII]/[SII] ratio, and the oxygen abundance (12 + log(O/H)). The data points are color coded to indicated the CHAOS galaxy. In each panel there is a general 1:1 agreement.
December 3, 2024 at 4:40 PM
astronoray.bsky.social
First, we need to estimate the ion. parameter and oxy. abundance. We know that the calibs. for O/H disagree with each other, and it turns out so do the ion. calibs.! It probably is caused by assumptions in the modeling process, old atomic data, stellar SEDs, and/or chemical abundances.
A panel of 6 scatter plots showing the relationship between O32 and the ionization parameter (log U). Each plot has black data points on it representing HII regions in NGC 628 as part of SIGNALS. Labels in the corner of each plot indicates the calibration used. In each panel, there is a general upwards trend. The x-axis ranges from -4 to 1, and the y-axis ranges from -6 to 0.
December 3, 2024 at 4:40 PM
astronoray.bsky.social
The data collected as part of SIGNALS is primed to tackle this question. Taken with SITELLE at CFHT, we've got data for all the strong optical emission lines across a huge FOV and great spectral (R~5000) and spatial (~35 pc) resolution. Below is our deep image of NGC 628 and some HII regions.
Composite image showing regions of interest in the spiral galaxy NGC 628. The right panel shows the full galaxy with marked boxes identifying two regions: Region #1 and Region #4. The left panels provide zoomed-in views of these regions, with color-coded maps highlighting the density and distribution of star-forming regions. Crosses mark the positions of individual sources, with brighter colors indicating higher density. Labels and a scale bar ("500 pc") are included for reference.
December 3, 2024 at 4:40 PM
astronoray.bsky.social
Variations in the oxygen abundance and ionization parameter are usually thought to be the dominant factors that produce emission line spectra. But are these two physically related? Turns out, people get different answers! Some say they're correlated, some say anti-correlated, others say no!
Scatter plot showing the relationship between the ionization parameter (log U) and oxygen abundance (12 + log(O/H)) in star-forming regions. Data points are color-coded, and show a general downward trend. Three lines are plotted for comparison: a green dashed line, a black dotted line, and a blue solid line, each representing different models or fits to the data. The x-axis ranges from 8.1 to 8.8, and the y-axis spans from -4.5 to -1.0. A density plot showing the relationship between the ionization parameter (log(U)) and oxygen abundance (12 + log(O/H)) for star-forming regions, labeled "a) N2O2-O3O2" in blue at the top. The color gradient ranges from dark purple (low density) to bright yellow (high density), indicating the concentration of data points. A green arrow points to a specific oxygen abundance value labeled "8.69" on the x-axis. The x-axis spans from approximately 8.25 to 9.00, and the y-axis ranges from -4.00 to -2.00. Scatter plot showing the relationship between the oxygen abundance (12 + log(O/H)) and ionization parameter (log U) in star-forming regions of six galaxies. Data points are color coded representing each of the six galaxies. All galaxies show a general upwards trend. The x-axis ranges from -3.8 to -2.6, and the y-axis ranges from approximately 8.2 to 9.2. Scatter plot showing a relationship labeled "[OIII]/[OII] vs. [NII]/[OII]" at the top in black text. The data points are color-coded, representing the data source. There is no trend apparent in the data. The x-axis range from 7 to 9.2, and the y-axis ranges from -3.5 to -1.5.
December 3, 2024 at 4:40 PM
astronoray.bsky.social
Hey y'all! My first paper as a postdoc has hit the arXiv today! As part of the SIGNALS collaboration, I used data we had for over 1500 HII regions in the galaxy NGC 628 to investigate the abundance-ionization correlation! Read about it here and on the arXiv!

arxiv.org/abs/2412.01680
Composite image showing regions of interest in the spiral galaxy NGC 628. The right panel shows the full galaxy with marked boxes identifying two regions: Region #1 and Region #4. The left panels provide zoomed-in views of these regions, with color-coded maps highlighting the density and distribution of star-forming regions. Crosses mark the positions of individual sources, with brighter colors indicating higher density. Labels and a scale bar ("500 pc") are included for reference.
December 3, 2024 at 4:40 PM
astronoray.bsky.social
Thankful for the soul, and thankful for the breath.
Thankful for this life, though it leads to death.
A picture of two people watching fireworks. The fireworks are exploding in the night sky, illuminating the surrounding trees and ground.
December 1, 2024 at 8:09 PM
astronoray.bsky.social
Thankful for the karma, and thankful for the faith.
Thankful for the values, no matter what it takes.
A picture of the starry night sky. Several bright points of light of various blues and whites fill the image.
December 1, 2024 at 8:09 PM
astronoray.bsky.social
Thankful for the clouds, thankful for the rains.
Thankful for the misery, and occasional pains.
A picture of a highway in the afternoon. In the distance, large clouds are dominating the skies that indicate rain and thunder.
December 1, 2024 at 8:09 PM
astronoray.bsky.social
Thankful for the wind, and thankful for the tree.
Thankful for the whispers, that set me free.
A picture of a wild grass with two trees dominate the foreground.
December 1, 2024 at 8:09 PM